While the Windows and Mac user interfaces are broadly similar, they do have subtle variations in day-to-day use that require some re-education for switchers. And because there are so many fewer Mac users than Windows users, help from friends and co-workers can be harder to obtain than it is for people switching the other way, to Windows from Mac.

So, here’s a quick tip sheet explaining a few of the most common differences in the daily use of Windows XP (MSFT), from which most people would be switching, and Apple’s (AAPL) Mac OS X Leopard, which switchers would be adopting.

This column isn’t an argument for making the switch to a Mac, merely an attempt to help those who have done so, or who are considering doing so. Of course, all Macs currently sold can run Windows and Windows programs concurrently with the Mac operating system. But this guide is for folks who intend to use their Macs primarily with Leopard, not Windows.

Menu Bars: In Windows, each program typically has its own menu bar. On the Mac, there’s a single menu bar at the top of the screen that changes, depending on which program you are actively using.

Task Bar: The equivalent of the Windows XP Task Bar on the Mac is the Dock. Unlike the Task Bar, which primarily holds icons representing open windows, the Mac Dock primarily holds icons of programs you use most often. To place a program onto the Dock, you just drag its icon there. To remove it, you just drag its icon off the Dock and it disappears in a puff of animated smoke.

Start Menu: There is no Start Menu on a Mac. Its functions are divided between the Dock and the Apple menu at the upper left of the Mac screen.

Control Panel: The Mac equivalent of the Windows Control Panel is called System Preferences, and it can be launched from either the Dock or the Apple menu.

Keyboard shortcuts: Common Windows keyboard commands, such as Ctrl-S for Save, Ctrl-P for Print, and many others, are also available on the Mac. However, instead of using the Control key, they use the Mac’s Command key, which bears either a cloverlike symbol or an Apple logo. So, on the Mac, for instance, Command-S is for Save.

Quitting programs: In Windows, you can quit a program by clicking on the red “X” in a square at the upper right corner of the window you’re using. But on the Mac, if you click on the equivalent button — a red “X” in a circle in the upper left corner — you are merely closing the window, not quitting the program. To quit the program, you must either select Quit from the leftmost menu or press the Command and “Q” keys together.

Maximizing windows: When you click on the blue maximize button in Windows XP, the window you are viewing occupies the whole screen. In Leopard, the equivalent button — a green circle at the upper left — increases a small window’s size to a footprint deemed optimal for its contents, which isn’t always the whole screen.

Switching programs: One common way to switch among running programs in Windows XP is to press Alt and Tab together. This displays icons of each running program and allows you to switch among them. On a Mac, the same trick can be performed by pressing the Command and Tab keys together. The Mac also has a terrific feature called Expose, which shows every open window at once, in miniature form, so you can navigate among them. You can trigger Expose in a number of ways, but the most common is to hit either the F9 key or the dedicated Expose key, depending on your Mac model.

Right-clicking: Contrary to common belief, the Mac has a right-click menu function, just like Windows. Most desktop Macs now come with a mouse that allows right-clicking, and you can use almost any two-button USB mouse with any modern Mac. If you are using a Mac laptop, which has only one button under the track pad, you can simulate a right-click by either holding down the Control key when you click, or by placing two fingers on the track pad while clicking. The latter technique, which I favor, must first be turned on in System Preferences.

Screen: Your desktop picture and screen saver on a Mac are set via a System Preference called Desktop & Screen Saver. Screen resolution is set in the Displays System Preference. In Windows XP, all of these things are included in the Display control panel.

For more information, Apple offers two Web sites. One is called Mac 101, and is at apple.com/support/mac101. The other is called Switch 101, and is at apple.com/support/switch101.

• Find all of Walt Mossberg’s columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com. Email him at mossberg@wsj.com.

That is the question that Mozilla, the nonprofit organization that makes the leading alternative browser, hopes to answer this month when it releases version 3.0 of its Firefox Web browser. In some tech-industry circles, Firefox already is preferred over Microsoft’s (MSFT) Internet Explorer and Apple’s (AAPL) Safari, but it still isn’t used by most people, and Mozilla is hoping to broaden its appeal.

The new version will be released simultaneously for Windows and the Mac’s OS X operating system, as well as for Linux. While each of the three editions will have the visual style of the operating system on which it runs, all three will have the same features.

I’ve been using prerelease versions of Firefox 3.0 for months, and have recently been testing a near-final version and comparing it closely to IE and to Safari. I have tested it on multiple Windows PCs and Macs, on desktops and laptops, over slow connections and fast ones. I have tried it with well over 100 Web sites.

My verdict is that Firefox 3.0 is the best Web browser out there right now, and that it tops the current versions of both IE and Safari in features, speed and security. It is easy to install and easy to use, even for a mainstream, non-technical user. It can be downloaded, free, at mozilla.com by clicking on “Firefox 3 Sneak Peek.”

This situation may change. Microsoft is working on a new version of IE, scheduled to be unveiled later this year, with some impressive new features. And Apple is always working on new iterations of Safari, though it is secretive and hasn’t disclosed its plans. But for now, in my view, Firefox 3.0 rules on both Windows and Mac.

I couldn’t find any significant downsides to Firefox 3.0. Every page I tried rendered properly and rapidly on both platforms. I ran into only one glitch, in a preference setting. That problem appeared on only one of my four test machines and was fixable with the help of Mozilla, albeit via a geeky method.

In the one or two cases where Firefox lacked a feature I thought important, such as the “auto fill” feature in Safari that can quickly fill out an online form, I was able to find an add-on that did the trick from Mozilla’s vast library of add-ons, which are written by people all over the world. (One caution: Some existing add-ons won’t work with the new version until their authors update them.)

When Firefox first came out, it was the fastest browser, but it lost that title over the years. However, in my tests, this new third version of Firefox regained the speed crown. It beat IE 7 handily on my test Windows computers and edged Safari slightly on my test Macs.

For example, using a new Dell (DELL) XPS One desktop, I opened identical folders containing the same 16 bookmarks on both IE 7 and Firefox 3.0. IE took 37 seconds to completely display the 16 pages, but the new Firefox did it in just 23 seconds. On a new Apple iMac, I did a similar, but more daunting, test — opening identical folders containing 24 bookmarks. Safari rendered all of the pages in 36 seconds, but the new Firefox finished the job in 32 seconds.

The latest Firefox has a number of new and improved features. If you type any word or phrase into its address bar, the browser instantly searches your history and bookmarks for a possible match, to save you from typing or combing through your bookmark list.

The whole process of managing bookmarks has been vastly simplified. Every Web address is accompanied by a star icon at the right. To bookmark the site, you just click the star once. No other action is required. To specify where to file the bookmark, you click the star twice. You also can remove bookmarks by clicking the star. And you can tag bookmarks with key words, to make it easier to find them.

There are also smart bookmark folders, which gather your most visited sites, or most recently bookmarked sites, automatically into folders. You also now can more easily back up and restore your bookmarks, complete with tags.

Security is also improved. The old version of Firefox would warn you when a site you were visiting appeared to be a fake, designed to steal your identity. (IE has a similar feature, though Safari doesn’t.) But Firefox 3.0 now warns you about sites that are known for trying to plant viruses, spyware and other malicious software on your computer, a warning the other big browsers don’t yet provide.

With one click, Firefox 3.0 also provides details about who owns the site you’re visiting, and whether it’s encrypted, if the site owner has adopted a special type of security certificate.

My bottom line: Even though you already have a built-in browser, Firefox 3.0 can improve your Web experience.

• Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.

But in recent weeks, I’ve been bombarded by reader emails asking for Mac-buying advice. So, here’s a quick guide — a sort of Mac FAQ — to shopping for a Macintosh. As with my Windows guides, this is aimed at average, mainstream users doing typical tasks, not techies or businesses or hobbyists.

Q. Who should consider a Mac?

A. Pretty much every average consumer using a computer should at least look at the Mac. It combines gorgeous hardware with an operating system I consider superior to Windows, with better built-in software. It can even run Windows programs if you buy and install a copy of Windows. And unless you do that, you won’t be vulnerable to the vast array of viruses and spyware that threaten Windows users. Only a handful, so far, have been written to run on the Mac operating system, OS X.

Q. Who shouldn’t consider the Mac?

A. People who spend much of their time playing cutting-edge games should stick to Windows computers, because there are far fewer games written for OS X. Apple doesn’t offer hardware tuned for serious gaming. People looking for the lowest-price PCs should also avoid the Mac, because Apple’s cheapest model, the Mac Mini, costs $599.

Another group that should shun Apple’s computers are people who depend for support on corporate IT departments that are either ignorant about, or hostile to, the Mac. Finally, if you know and like Windows, and expect mainly to use Windows programs, stick with a Windows PC.

Q. Can I run Microsoft Office on a Mac?

A. Yes. Microsoft makes a Mac version of Office, which uses the same file formats that Word, Excel and PowerPoint for Windows have used for years. A new version of Office for the Mac is due in January and it will handle the new file formats Microsoft introduced this year. But the Mac version of Office omits Outlook. It has a similar program called Entourage, but Entourage can’t use Outlook data files. If you want a Mac but must have Outlook, you will have to install Windows.

Q. Can I use all my Windows files on a Mac?

A. Out of the box, Macs can handle all the common file types Windows machines create, including text files, pictures, songs and Adobe PDF files. The Mac even comes with a simple word processor that can open Microsoft Word files.

However, some specialized Windows programs create files that the Mac can’t handle out of the box. And the Mac version of Quicken has a difficult time properly handling Windows Quicken files. If you are a Quicken fan, install Windows and run the Windows version.

Q. Can I mix Macs and Windows on the same home network?

A. Macs can plug and play with most brand-name wired and wireless routers, and can share Internet connections with Windows PCs.

Q. How are Macs at Web surfing?

A. Fine. Apple’s built-in Safari browser is very good and the Mac version of Firefox is essentially identical to the Windows version. However, Macs lack an up-to-date version of Microsoft’s Internet Explorer, so you will have to install Windows if you need IE.

Q. Can Macs run standard peripheral hardware?

A. Macs can run nearly all keyboards, mice and printers that use USB connections, even ones that don’t explicitly say they run on Macs.

Q. What desktops does Apple offer for consumers?

A. Apple’s main consumer desktop is the one-piece iMac, which I regard as the best consumer desktop on the market. It comes in four models, with built-in 20-inch or 24-inch, flat-panel screens at starting prices ranging from $1,199 to $2,299.

Q. How about Mac laptops?

A. There are two. The entry-level MacBook has a 13-inch screen and a starting price of $1,099. The high-end MacBook Pro comes with either a 15-inch or 17-inch screen and starts at $1,999. Apple currently doesn’t offer a smaller laptop for road warriors, but there are persistent rumors that it will do so soon.

Q. What minimum specs should I look for on a Mac?

A. All Macs come with at least one gigabyte of memory — twice the minimum required for the new version of OS X, called Leopard. If you can, get two gigabytes. Apple charges a lot for extra memory, but you can buy it for less at stores and online providers.

Macs use the same dual-core Intel processors and graphics systems as many mainstream Windows computers; and, as with Windows, I wouldn’t pay extra for greater processor speed.

The iMac comes with at least a 250-gigabyte hard disk, and Mac laptop hard disks start at 80 gigabytes. Mainstream Windows desktops typically start with larger hard disks. But Apple offers much larger disks as options, which you should consider if you store a lot of photos, music and video files.

Email me at mossberg@wsj.com. Find all my columns and videos online free at the new All Things Digital Web site, http://walt.allthingsd.com.

There are several reasons for this, including the security problems in the dominant Windows platform from Microsoft; spillover from Apple’s blistering success with its iPod music players; the fact that Macs can now run Windows programs; and Apple’s highly successful chain of company-owned retail stores.

But another key factor has been the Mac operating system, called OS X, which came out in 2001. It has proved to be as powerful and versatile for mainstream consumers as Windows, yet easier to use and more secure. And Apple has upgraded OS X far more rapidly than Microsoft Inc. has upgraded Windows, bringing out major new releases roughly every 18 months, while Microsoft struggled for more than five years to produce the latest Windows iteration, Vista, which came out in January.

On Friday evening, Apple will release yet another new version of OS X, called Leopard, to replace the current version, known as Tiger. I’ve been testing Leopard, and while it is an evolutionary, not a revolutionary, release, I believe it builds on Apple’s quality advantage over Windows. In my view, Leopard is better and faster than Vista, with a set of new features that make Macs even easier to use.

Leopard will come preinstalled on all new Macs. It can also be purchased for $129 as an upgrade to existing Macs that, depending on configuration, can be as many as six years old. Unlike Vista, which is sold in four noncorporate upgrade versions ranging from a $100 stripped-down “basic” edition to a $259 deluxe “ultimate” edition, there’s only one version of Leopard. It includes all the features, from those aimed at novices to those aimed at power users.

For me, the marquee features in Leopard are a new function called Time Machine that automatically backs up your entire computer in the background; two new methods, called Cover Flow and Quick Look, for rapidly viewing the contents of files without opening any programs; and new techniques that allow you to access the files in, and to remotely control, other computers on your network or connected over the Internet with a few clicks and no technical expertise.

Plus, Apple’s free software for running Windows on a Mac, called Boot Camp, which was formerly an add-on users had to download and install, is now built right into the operating system. And, in my tests, the third-party Fusion program for running Windows and Mac programs simultaneously continued to work fine in Leopard.

I did notice a few drawbacks, but they were minor. The menu bar is now translucent, which can make it hard to see the items it contains if your desktop picture has dark areas at the top. The new folder icons are dull and flat and less attractive than Vista’s or their predecessors on the Mac. While Time Machine can perform backups over a network, the backup destination can only be a hard disk connected to a Mac running Leopard. And, on the Web, I ran into one site where the fonts on part of the page were illegible, a problem Apple says is known and rare and that I expect it will fix.

While Apple claims the new system includes more than 300 new features, there is nothing on the list that could be considered startling or a major breakthrough. Some of Leopard’s features are unique, but many others — such as backing up data and quickly viewing files — have been available on both Windows and the Mac via third-party programs or hard-to-find geeky methods buried in the operating systems. Leopard has made them easy to find and use.

When I upgraded my personal iMac desktop to Leopard, it took less than an hour, and after the process was complete, all my programs, including the Mac version of Microsoft Office, the Firefox Web browser and Adobe Reader, worked rapidly and fine. I was still able to run Windows XP via Fusion. And my previous installation of Boot Camp, which turns the iMac into a speedy, full-fledged Vista machine after a reboot, worked perfectly. All my Vista programs and files continued to function properly.

With Cover Flow, users get a visual preview of a computer’s files without having to open programs.

In fact, every piece of software and hardware I tried on two Leopard-equipped Macs — a loaned laptop from Apple and my own upgraded iMac — worked fine, exhibiting none of the compatibility problems that continue to plague Vista. My old Hewlett-Packard inkjet printer, for which Vista lacks the proper software, worked instantly in Leopard, even over the network. And, unlike with Vista, it was able to print on both sides of the page. I popped my old Verizon cellphone modem card into the test Leopard laptop and it worked, too, with no software installation or tweaking.

Leopard felt about as fast as Tiger, and it started up much faster than Vista in my tests. I compared a MacBook Pro laptop with Leopard preinstalled to a Sony Vaio laptop with Vista preinstalled. Even though I had cleared out all of the useless trial software Sony had placed on the Vaio, it still started up painfully slowly compared with the Leopard laptop.

It took the Vista machine nearly two minutes to perform a cold start and be ready to run, including connecting to my wireless network. The Leopard laptop was up, running and connected to the network in 38 seconds. In a test of restarting the two laptops after they had been running an email program, a Web browser and a word processor, the Sony with Vista took three minutes and 29 seconds, while the Apple running Leopard took one minute and five seconds.

Here’s a rundown of some of Leopard’s key features. Much more detailed information is available at apple.com/macosx.

File management: Apple’s Finder, the equivalent of Explorer in Windows, now offers two new ways to quickly see what your files contain. You can still view them as icons or lists. But you can also use Cover Flow, the same system Apple uses in iTunes and on the iPhone to display album covers for music. In Leopard, a large preview of each file you select appears above the list of files in a folder, and you can rapidly scroll through these icons. These previews are live, and their contents can be viewed without opening the program that is normally needed to display them.

Time Machine backs up files.

For instance, if the file is a video, you can just click on it, and it will play. If it’s a multipage PDF file, you can click on it, and arrows will appear allowing you to flip through the pages.

An even better and deeper look can be obtained using a feature called Quick Look. Just hit the space bar or click on a toolbar icon, and a preview of any selected file zooms out. You can even view multiple sheets in an Excel file via Quick Look without launching Excel.

Another quick new way to see your files is available in the Dock, the Mac’s equivalent of the Windows Task Bar. Here, any folder you place on the right side of the dock will display its contents, after a single click, either as a grid of icons displaying miniversions of the file or as a “fan,” or arc, of such icons. These special Dock folders are called “Stacks.” Leopard includes one by default that is the destination for everything you download from the Internet, so your desktop will no longer get cluttered with downloads,

Time Machine: This built-in feature will continuously back up all of the contents of your Mac to either an external hard drive directly connected to the computer, or to a hard disk connected to another Mac running Leopard that’s on your network. The initial backup, in my tests, took all night, but after that, the system updates the backups hourly and I didn’t notice any slowdown during the process.

To recover any file you deleted, you simply click on the Time Machine icon, and you are taken to a view that shows file folders — or your email or address book or photo collection — in a stack of windows that appear to go on infinitely. You click on an arrow and the stack of windows zooms until you arrive at the last view in which the missing file existed. Then, you click “restore,” and the file is recovered in your normal desktop view. You can also restore whole folders, groups of files, or even an entire hard disk.

Shared computers: In Leopard, any computer that has been set to be shared on your network shows up on the left side of every Finder window. Click on it, and you can access whatever folders have been shared on those machines. Depending on the remote computer’s security settings, you may first have to enter a user name and password. It’s the simplest method I’ve ever seen for accessing other computers on a network. And it works with Windows PCs as well as Macs. When I first turned on the Leopard laptop in my office, it immediately found a shared folder on my colleague’s old Dell running Windows XP. She hadn’t even remembered sharing the folder, which contained files from 2003.

You can copy or move files to and from these shared computers, or view their contents with Cover Flow and Quick Look, or open them in programs on your own computer.

If you are a member of Apple’s optional .Mac service, which costs $100 a year, you can use a feature called “Back to My Mac,” which can access your Macs from thousands of miles away over the Internet. However, this feature works only over certain kinds of routers (not all of them Apple’s) and, as my router didn’t qualify, I couldn’t test it.

Remote control: For any Mac in your shared-computers list for which you have permission, you can take over the screen by simply clicking on a button called “Share Screen.” You can also remotely control distant Macs over the Internet using Apple’s built-in iChat instant messaging program, as long as you have permission and the Macs are running Leopard.

Stacks displays the files in folders in the dock.

iChat: Apple now allows you to use its instant messaging program with Google Talk as well as AOL’s AIM service, and you can set up a video chat in which you can present a slide show or display a document. You can also add special backgrounds that can make it look as though you’re someplace else, like Paris. In my tests, this even worked with someone on the other end using a Windows XP computer running the latest version of AIM.

Spaces: In order to cut down desktop clutter, Leopard lets you set up as many as 16 different desktops that can run simultaneously, with different programs open in each. You switch among these desktops by using keyboard commands or a menu.

For instance, you might have your iPhoto and iTunes running in one “space,” or desktop, your Web browser and email program in another, and Windows XP in another.

Leopard isn’t a must-have for current Mac owners, but it adds a lot of value. For new Mac buyers, it makes switching even more attractive.

Email me at mossberg@wsj.com. Find all my columns and videos online free at the new All Things Digital web site, http://walt.allthingsd.com.

Back in January, when I reviewed the massive new operating system, which took more than five years to develop, I called it “unexciting” because many of the breakthrough features Microsoft had planned for it had been jettisoned, and most of the rest were already present in the rival Apple Macintosh operating system, OS X.

But I also said it was “worthy,” and better than prior versions of Windows, because it has a stronger security system under the hood and better integrated searching.

Over the ensuing months, however, Vista has proved to be a disappointment, even though Microsoft says it’s selling like hotcakes. Based on my own experience and on reports from readers, it’s clear that many Vista PCs start up more slowly than new PCs running its predecessor, Windows XP, or than even well-worn Macs. And there is still a significant compatibility problem: Too many software and hardware products still don’t run, or don’t run properly, with Vista.

So, if you’re shopping for a new Windows computer, one of your first decisions is whether you want to get Vista, which comes on almost all new models, or to stick with Windows XP. PC makers are still offering XP on a few new consumer PCs. For instance, Dell offers four consumer laptops and two consumer desktops that can be ordered with XP.

Buying XP will likely result in fewer frustrations in the short run. But buying Vista may be the better choice for the long run. Over time, more and more products will be released that are tailored to the new system.

Your other option is to shun the Windows dilemma and buy a Macintosh. I regard the Mac operating system as superior to Windows, and Apple embeds it in beautifully designed machines. Macs have been spared the plague of viruses and spyware that afflicts Windows, and have better built-in multimedia software.

But, if you’re thinking of buying a Mac, it makes sense to wait a few weeks or months to gauge the early reviews and user reactions to Apple’s own new version of its operating system, called Leopard, due out Oct. 26. After that date, Apple won’t build in the current version of OS X, called Tiger, on new machines.

Here are some tips if you’re shopping for a new Windows PC this fall. They apply to desktop PCs and to most mainstream laptops, though there are additional considerations, such as size and weight and battery life, for smaller laptops meant primarily for travel. As always, these recommendations are intended for average consumers doing average tasks, not for heavy gamers, video professionals, or corporate buyers.

Operating system: If you opt for Vista, the best choice for average consumers is a version called Home Premium, which includes all of the new graphics and multimedia features. Many low-end PCs have only a stripped-down version called Home Basic. Some people may need Vista Business, a version that can link to some kinds of corporate networks that the two Home varieties can’t. If your budget allows, you can get an expensive version called Ultimate that includes the features of both the Home and Business versions.

Junk software: Most Windows consumer models are stuffed with “craplets” — crippled trial versions of programs. They take up space and can slow down the machine. One way to avoid these is to buy a so-called business PC, like one of Dell’s new Vostro models. Dell also allows you to opt out of trial software, especially when ordering its pricier XPS models. Many other manufacturers make this hard or impossible, especially if you buy a PC at a retail store. But the stores may clean up a new PC for a fee.

Memory: Buy at least one gigabyte of memory for Home Basic and at least two gigabytes for all other Vista versions.

Video: Vista’s flashy graphical interface works best with a separate, or “discrete,” graphics card that has its own memory. Some “integrated” graphics systems work fine, too, but they claim some of your main memory via an approach called shared memory.

Processor: Any “dual-core” processor from Intel or AMD should be fine for Vista. Don’t worry about processor speed. Buying added memory does more for performance.

Hard drive: Don’t scrimp on storage space, unless you are absolutely certain you won’t be saving many photos, songs or videos. Even an average PC should come with 300 gigabytes of hard-disk space for a reasonable price.

Performance: If you’re shopping in a retail store, try to check the performance rating Microsoft builds into Vista. It’s available by clicking “Show more details” in Vista’s “Welcome Center” screen. If this rating is below 3.0 on a Home Premium model, avoid the computer. For best results, shoot for 3.5 or higher.

Price: You can get a bargain-basement computer for under $400. But, for a versatile Vista PC with Home Premium, two gigabytes of memory, discrete video, a large hard disk and a dual-core processor, you should expect to spend $800 or more.

Email me at mossberg@wsj.com. Find all my columns and videos online free at the new All Things Digital web site, http://walt.allthingsd.com.

So, I have steered away from recommending Linux, the free computer operating system that is the darling of many techies and IT managers, and a challenger to Microsoft’s dominant Windows and Apple’s resurgent Macintosh operating system, OS X. Linux, which runs on the same hardware as Windows, has always required much more technical expertise and a yen for tinkering than average users possess.

Lately, however, I’ve received a steady stream of emails from readers urging me to take a look at a variant of Linux called Ubuntu, which, these folks claimed, is finally polished enough for a mainstream user to handle. My interest increased when Dell began to sell a few computer models preloaded with Ubuntu instead of Windows.

I’ve been testing one of those Dell Ubuntu computers, a laptop called the Inspiron 1420N. I evaluated it strictly from the point of view of an average user, someone who wouldn’t want to enter text commands, hunt the Web for drivers and enabling software, or learn a whole new user interface. I focused on Ubuntu and the software programs that come bundled with it, not on the hardware, which is a pretty typical Dell laptop.

My verdict: Even in the relatively slick Ubuntu variation, Linux is still too rough around the edges for the vast majority of computer users. While Ubuntu looks a lot like Windows or Mac OS X, it is full of little complications and hassles that will quickly frustrate most people who just want to use their computers, not maintain or tweak them.

Before every passionate Linux fan attacks that conclusion, let me note that even the folks who make and sell Ubuntu agree with it. Mark Shuttleworth, the South African-born founder of the Ubuntu project, told me this week that “it would be reasonable to say that this is not ready for the mass market.” And Dell’s Web site for its Ubuntu computers warns that these machines are for “for advanced users and tech enthusiasts.”

So, what do I mean when I say Ubuntu is too rough around the edges for average users? Here are some examples.

There is no control panel for adjusting the way the touch pad works, and I found it so sensitive that I was constantly launching programs and opening windows accidentally by touching the thing. Every time the computer awoke from sleep, the volume control software crashed and had to be reloaded.

When I tried to play common audio and video files, such as MP3 songs, I was told I had to first download special files called codecs that are built into Windows and Mac computers. I was warned that some of these codecs might be “bad” or “ugly.”

To get the computer to recognize my Kodak camera and Apple iPod, I had to reboot it several times. When it did find the iPod, it wasn’t able to synchronize with it. Playing videos was a bad experience, with lots of flickering and freezing. Oh, and there’s no built-in software for playing commercial DVDs.

The Ubuntu-equipped Inspiron 1420N starts at $744, but the configuration that Dell lent me for testing sells for $1,415. The same unit equipped with Windows Vista costs $1,524. The Ubuntu version includes OpenOffice, the free office suite that competes with Microsoft Office. Dell charges an added $149 for Microsoft Office.

Ubuntu and other versions of Linux have several advantages. Unlike Windows and OS X, they’re free. Unlike Mac OS X, they can be run on the least-expensive popular hardware configurations. Unlike Windows, but like the Mac, they are essentially free of viruses and spyware. And unlike Windows and Mac OS X, they are built and constantly improved by a world-wide network of developers, professional and amateur — the so-called open-source concept that produced the excellent Firefox Web browser.

It makes sense that all the best software brains can’t be located in just two places: Redmond, Wash., where Microsoft is based, and Cupertino, Calif., Apple’s base. And plenty of people reading this have had lots of frustrations with the two better-known operating systems, especially Windows, whose latest iteration, Vista, is disappointing in many ways.

But open source is a two-edged sword. While it draws on smart developers from many places, nobody is ultimately responsible for the quality of the product, and open-source developers often have an imperfect feel for how average people use software. A European company called Canonical is the “commercial sponsor” of Ubuntu and provides support. But it’s largely focused on corporate and techie users. Average Ubuntu users are likely to have to wade through online forums, often written in technical language, to get help.

Dell and Canonical tell me there are complex workarounds for some of the problems I encountered, and that built-in improvements are planned for others. But for now, I still advise mainstream, nontechnical users to avoid Linux.

Email me at mossberg@wsj.com. Find all my columns and videos online free at the new All Things Digital web site, http://walt.allthingsd.com.