The arrival of a large update like this isn’t a sign of trouble, or even unusual. Microsoft has routinely issued these large “service packs” periodically for Windows. And just this week, its competitor, Apple, unleashed an even larger update for its new operating system, Leopard.

Even though they can take a long time to download and install, such updates are generally a good thing for consumers. Microsoft will automatically deliver SP1, as the company calls it, through its normal updating mechanism, built into Windows. The update is free.

However, based on my tests of Vista SP1, I believe that for most average consumers, it will likely be a nonevent, and for others it will be disappointing. Many of its benefits are aimed at corporations and power users, or are under-the-hood fixes that are hard to discern. For mainstream users, it adds no significant, visible features to Vista, and changes little or nothing about the way the operating system looks and works.

Also, SP1 doesn’t resolve some of the most annoying flaws in Vista, including slow start-ups and reboots, and a security system that nags you too much and requires add-on anti-virus software. I guess these problems will either never be fixed fully or will have to wait for SP2.

While Vista SP1 does deliver some performance improvements in certain scenarios, it can actually temporarily degrade performance — including making reboots even slower — because of a quirk in the update process. This slowdown should go away in a few days, the company says.

On balance, the update is probably worth installing, especially since Microsoft will deliver it automatically. But I wouldn’t rush to grab it and I wouldn’t expect much from it. One note: you can’t install SP1 until you have installed a couple of other patches first. These will also be distributed automatically.

I installed Vista SP1 on two computers that had come with the original Vista preinstalled: a 10-month-old Sony Vaio SZ laptop and a two-month-old Dell XPS One desktop. Because the automatic download distribution isn’t yet in place, Microsoft sent me the update on a disk, which also included the prerequisite patches. In each case, the upgrade took a little over an hour and went smoothly. During the process, the computers rebooted multiple times, but it was all automatic and didn’t require user intervention.

After the installation, the computers functioned normally. I tested three of the performance improvements Microsoft claims for SP1. The first involved speeding up the copying of hefty folders containing large numbers of files. On both machines, copying a folder containing over 700 files totaling almost 700 megabytes took less than half as long with SP1 as it had with the original Vista.

I also tested how long it took both machines to awaken from a hibernation or sleep state and be ready for work. For these tests, I began with each machine running Microsoft Word, Microsoft Outlook and the Firefox Web browser, then I forced them into sleep and hibernation mode.

By my definition, “ready for work” means that Vista’s circular delay indicator has gone away, the software that loads at start-up has finished launching and the computer has fully reconnected to its wired or wireless network. On both of my test machines, SP1 improved the recovery time from sleep or hibernation, shaving one to 10 seconds from the procedures.

Microsoft doesn’t claim SP1 will improve the speed of cold starts and reboots under Vista, but I tested these anyway. To my horror, I found that SP1 actually made rebooting — already slower than on comparable Windows XP computers or Macintoshes — even slower.

Microsoft explained that this was due to the fact that installing SP1 erases certain data used by Vista to speed up program launching. It takes the system a few days to build this data back up, the company says. Until then, it says, overall performance, including reboots, can be slower under SP1 than under original Vista.

Microsoft provided me with a method that would rebuild this program-launching data more quickly, at least for the common programs I was using in my tests. Once I followed that method, rebooting time returned to its former state — still too slow for my taste, but at least not worse.

In briefing me on SP1, Microsoft made a big point of saying that great progress had been made in the past year in making Vista work properly with add-on devices, such as printers. I tried my 2003-vintage Hewlett-Packard printer, which hadn’t worked properly with the original Vista. It still didn’t work well with SP1.

So, Vista SP1 is a step forward, at least after a few days of use. But it’s not a big step.

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.

The most tangible example of this new approach is Dell’s XPS One desktop — an elegant, handsome, cleverly designed one-piece computer. If it didn’t have the Dell logo on it, the XPS One might be mistaken for a product of the PC industry’s design leaders, Apple or Sony.

Like Apple’s iconic iMac, the XPS One looks like it’s simply a sleek, flat-panel monitor. The guts of the computer have been stuffed into the back of the screen.

But this new Dell is no mere iMac clone. It makes its own style statement, even though it shares the same 20-inch widescreen display and a similar Intel dual-core processor with the base-model iMac. Where the iMac is squarish and silver, the XPS One is all black and rectangular, with speakers attached to the sides and a wide glass base. It looks more like a small TV set than a computer and, in fact, comes with a built-in TV tuner.

In my tests, I found the XPS One to be much better designed and equipped than Gateway’s iMac competitor, also called the One. In fact, the Dell XPS One is the first Windows all-in-one desktop I’ve tested that I believe matches or exceeds the iMac in hardware design. That’s no small feat, especially coming from Dell.

Unlike the Apple, for example, the Dell has a built-in slot for camera memory cards. It comes standard with a wireless keyboard and mouse, which cost extra on the iMac. Its screen can be turned off with the touch of a button without turning off the computer itself. Its USB and headphone ports are arrayed conveniently on the side, instead of mainly at the rear, as on the iMac.

And, when you wave your hand in front of the black border to the right of the screen on the XPS One, a set of blue, back-lit touch controls magically appear for controlling the playback of music or video. They go away after a few seconds. The Dell also comes with a free year of 10 gigabytes of online backup.

For my tests, I used the least expensive standard configuration of the XPS One, which can be ordered for $1,499 at dell.com/theonepc. It came with two gigabytes of memory (twice the comparable iMac’s standard amount), a 250 gigabyte hard disk and Wi-Fi wireless networking, unusual in Windows desktops.

The computer performed crisply and well for me. I installed several popular third-party programs that weren’t included, such as Microsoft Office, the Firefox Web browser, Apple’s iTunes and Adobe Reader. All worked fine.

I also successfully tested the built-in TV function, which requires a cumbersome external attachment to work with a cable box. I was able to view and record TV shows, something you can’t do out of the box on an iMac.

I still recommend the iMac over the XPS One for several reasons other than hardware design. First, there’s the software. I believe Apple’s operating system, Leopard, is superior to the new Windows Vista operating system, the only choice on the XPS One. In my tests, a reboot of the XPS One took more than twice as long as a reboot of the iMac.

And I regard Apple’s built-in software, especially the iLife multimedia suite, as superior to the Dell’s built-in software, which includes a group of Adobe multimedia programs that are less well integrated and more complex.

The XPS One, unlike the iMac, also came with a bunch of craplets — trial software like Yahoo Music and come-ons for online services like NetZero.

Second, the iMac, unlike the Dell, is immune to the vast majority of malicious software floating around, so you don’t have to run annoying, memory-hogging security programs. The first time I turned on the beautiful Dell I was met with a warning that I had “multiple security problems,” and was led to install a security suite in a complex and tedious process.

Third, defying popular perception, the iMac costs less than the XPS One. The base, 20-inch iMac costs $1,199 — about $300 less. And even if you double the memory, and add a wireless keyboard and mouse to match the Dell, it’s still $1,399 — $100 less than the base XPS One (though Dell is currently running a sale that wipes out the $100 gap). Even the cheapest iMac has a dedicated video card with its own memory, something the base XPS One lacks.

Plus, while Dell offers only 20-inch screens on the XPS One, Apple has higher-end iMacs with huge 24-inch screens for the same price, or less, than the higher-end Dells.

Still, if you want a stylish Windows Vista machine that runs well and won’t cost a fortune, the XPS One fits the bill, despite its unlikely heritage.

• 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.

But for some folks, getting the most out of these players takes too much work or too much money. Converting CDs to music files takes time, as does selecting and downloading tracks from online music services, and synchronizing players with PCs. Creating great playlists also takes time and effort. Some people prefer the old radio model, where songs are programmed by somebody else and you just listen.

Plus, whether you download songs for 99 cents apiece, use a subscription download service for $15 a month, or sign up for satellite radio at $13 a month, the costs to keep your portable player filled legally can add up quickly.

So a new kind of portable player, one for more passive and budget-minded users, is slated to arrive late next month. It’s called the Slacker Personal Radio, and its name is meant to refer to people of any age who just want to sit back and listen instead of actively managing their music.

The new Slacker players will come in three models, ranging from $200 to $300, depending on capacity. But the music they play will be absolutely free, contained in preprogrammed Internet radio stations instead of individually selected songs and albums. The stations will be automatically refreshed with new tunes via a wireless connection built right into the device. You’ll have to be near a hot spot for these updates. But you won’t need a hot spot just to hear your music, because the songs are cached on the device. And you’ll never have to plug it into a computer.

The player is tied to Slacker’s free Internet radio service, slacker.com, which is already up and running, and allows you to listen to music via any standard Windows or Mac Web browser. Using the service, you can personalize your player by selecting from over 100 canned stations or by creating stations based around any of 10,000 artists. These stations will be beamed to your player wirelessly. You can even choose which stations are loaded onto your player before the company ships it to you.

The company, a San Diego-based start-up of the same name, hopes to make money eventually via advertising on the player, and by selling an optional paid premium plan that offers some additional features.

I’ve been testing a prototype of the chunky, black plastic Slacker player, which is dominated by a four-inch color screen. It has two redundant navigation systems: a touch-sensitive strip at the side of the screen and a wheel on one edge. It provides a rich listening experience, including album art and other photos, artist bios and album reviews. The sound is good, and the Wi-Fi wireless connection worked in both my home and office.

The two prototype Slacker units I tried, however, were hobbled by bugs and glitches that the company must expunge by the release date, which was originally slated to be this month. For instance, the players sometimes failed to wake up after going to sleep, requiring a reboot. The touch strip was unreliable. One player failed several times to connect to my account. Battery life is well below Slacker’s goal of 12 hours between charges. The company says it is aware of these problems, and pledges all will be fixed.

Slacker isn’t the only portable player to offer programmed Internet stations. The Rhapsody service offers similar, customizable Internet-based stations on a couple of players. And both the Sirius and XM satellite-radio networks offer portable players for listening to their stations, although the stations can’t be customized. But all of these players require monthly subscription payments, while Slacker’s stations are free.

The Slacker Radio

Because Slacker is based on Internet radio, it has some limitations imposed by the rules governing that format. For example, you can’t specify a particular song to play, or skip back to repeat a song. And you can skip ahead only six times per station per hour. Even if you create a station around a particular artist, the station will mainly be filled with artists the service considers similar. Songs by the artist you selected will be played only four times every three hours.

The player has a “heart button” for designating a song for frequent play and a “ban” button to eliminate the songs you hate.

If you’re willing to pay, or put in more effort, you can get additional capabilities. For example, Slacker players can hold and play some of your own songs, in addition to programmed stations, if you download a free Windows software program. And, if you sign up for the premium option at $7.50 a month, you get unlimited song-skipping, no ads, and the ability to save favorite songs on the device and play them as often as you like.

But the basic idea of Slacker is to make portable listening free of effort and of service charges. If the company can wring the bugs out of its new player and if its ads aren’t too annoying, that formula may appeal to some busy music lovers.

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.