Apple and Sony are the usual suspects. Microsoft and Intel, which dominate the industry, rarely make the list of design risk-takers. So the latter two leaders deserve credit for cooking up a whole new type of Windows computer — a machine that’s smaller than the smallest mainstream laptop — the Ultra Mobile PC, or UMPC. The first UMPC for the U.S. market, the Samsung Q1, goes on sale next week at Best Buy’s Web site.

The idea behind the UMPC is that it’s so small, yet so full-featured, it can replace a laptop. It’s meant to fit in places a laptop won’t, or simply to be held in your hands. It is also supposed to be a cool multimedia device for watching video or listening to music.

Unfortunately, the Samsung Q1 is so deeply flawed in key respects that it amounts to little more than a toy for techies. For everyone else, it’s impractical and frustrating. Unless the UMPC can evolve significantly beyond this first effort, it may wind up as a footnote in the history of personal computers, rather than an exciting new category.

The Q1 is sleek and attractive. It’s about the size of a hardcover book, only narrower, and is clad in shiny black plastic with silver accents. Most of the unit is occupied by a wide-angle color touch screen that measures 7 inches diagonally. Overall, it’s about 9 inches long, 5.5 inches wide and just under an inch thick. It weighs a scant 1.7 pounds.

Inside, the little machine runs a full version of the Tablet edition of Windows XP. In fact, the UMPC, which Microsoft had code-named Origami, is really just a small Tablet PC. That’s a good thing, because many of the Tablets shipped so far have been too big and bulky to use comfortably as electronic notepads or document readers, which are the main functions of tablet computers.

The Q1 uses a slow, low-end Intel processor, a Celeron running at 900 megahertz. But it was adequate for the common tasks I tested — Web surfing, email, playback of audio and video files. There’s also a 40 gigabyte hard disk, 512 megabytes of memory, Wi-Fi and Bluetooth wireless networking, an Ethernet port, two USB ports and a slot for Compact Flash memory cards.

There’s no embedded cellphone modem and no slot for adding an external one. The Q1 also lacks an internal DVD drive. An external drive can be added for $219, but it’s an extra piece to carry and plug in.

You operate the Q1 like a PDA — by manipulating icons on the screen and writing on the screen using either a simple plastic stylus or your fingers. It lacks a built-in keyboard and doesn’t come with a mouse.

In my tests, the Wi-Fi and wired networking worked well and were fast. All the applications I tried launched fine and worked fine. Video clips looked pretty good on the screen, and the stereo speakers, though small, did a decent job.

So what are the Q1’s big flaws? The first is price. Microsoft’s designers set a target retail price of $500, but Samsung is charging more than double that amount — $1,099. That’s more than many laptops cost, and much more than PDAs or smart phones. In fairness, the lightest laptops tend to cost more — $1,500 to $2,500. But $1,099 is still a lot for a UMPC.

The second is battery life. In my harsh battery test, the Q1 lasted just two hours and two minutes. That means that, in normal use, it might approach three hours, if you’re lucky. You can buy a larger battery for $119, but it adds bulk to the computer and nudges the weight up to two pounds, almost as heavy as the lightest standard laptops.

The third is the lack of a keyboard. Without a keyboard, many standard tasks in Windows are simply a huge hassle. You can’t really do word processing at speeds most people are used to. And email is a constant frustration. Yes, the Q1 has handwriting recognition, but it’s cumbersome. And there’s a semicircular onscreen keyboard, but it takes work to use it well.

Most Tablet PCs include a keyboard. Even the tiny OQO computer has a keyboard, as do Treos and BlackBerrys. How come the combined brains at Microsoft, Intel and Samsung couldn’t build one into the Q1? You can plug in an external keyboard, but that makes the machine ungainly.

The fourth big flaw is the screen. Its resolution is too low to see much material at a glance. Often, you can’t even see the OK button at the bottom of open Windows. There is a way to increase the resolution, but it results in distorted graphics and fuzzy text.

Finally, the navigation buttons and controls on the Q1 are awful. There’s a control that moves the cursor, and another that acts like a Return key. But there are no direct equivalents of the left and right mouse buttons. To emulate a mouse button, you have to hold down two of the Q1 buttons simultaneously.

My advice is to skip the Q1, and hope that the next generation of the UMPC will be better.

• Email me at mossberg@wsj.com.

The makers of the gadgets have been trying to move them into the mainstream. GPS navigation has shown up in cellphones, personal digital assistants and fitness gear. But these new incarnations have failed to make GPS navigation a big hit with average people.

Now, one of the top makers of GPS receivers, Kansas-based Garmin Ltd., has taken a bold step toward that mainstream. It has created a small, sleek portable GPS receiver meant to be carried everywhere. This new gadget has been recast as a “personal travel assistant,” to shed its geeky roots. And it includes not only satellite navigation and mapping, but also a built-in music player, photo viewer, U.S. travel guide, audio-book reader, language translator, currency converter and more.

I’ve been testing this new gadget, called the Nüvi 350, in and out of my car, and I find myself torn about it. On the plus side, it’s really well designed and has a good, simple user interface. It does what it promises for the most part, and requires no setup or technical knowledge.

But at $900, the Nüvi costs as much as a decent laptop, and more than double that of such established portable prodigies as Palm’s Treo smart phone or Apple’s top-of-the-line iPod.

And the Nüvi’s core function, GPS navigation, is still too crude and clumsy to command such a high price from a mainstream, casual user. This is a problem with every GPS receiver I’ve tested, not just the Nüvi. Too often, all of them suggest routes that a savvy local driver would immediately recognize as too long or too slow or too likely to place you into heavy traffic. That level of inaccuracy might be fine in a $150 device, but $900 is a lot to pay for roundabout directions.

The Nüvi is a rectangular, silver-colored plastic device that’s less than four inches wide, less than three inches high and less than an inch deep. It weighs about five ounces. Its front surface is dominated by a large, 3.5-inch color screen that’s bright and vivid. Other than a power button on the top, there are no buttons, switches or scrolling devices on the Nüvi. Everything is controlled by touching options on the screen.

The only features on the outside are a flip-up GPS antenna on the rear — a squarish panel of silver-colored plastic — and three openings on the side that accept an SD memory card, headphones and the cables that charge the Nüvi or connect it to a computer.

The Nüvi starts up quickly and, more importantly, acquires the signal from the satellites in seconds, a vast improvement over the last Garmin model I tested some years ago. The main menu has just three entries: Where to?, View Map, and Travel Kit. The first is where you enter a destination, and the last opens a submenu that includes all of the Nüvi’s nonmapping functions.

Using the included suction-cup mount, I placed the Nüvi inside the windshield of my car, just to the left of the steering wheel. For a few days I breezed around the Washington, D.C., area, letting the Nüvi direct me to and from my house, my office and other locations. Its maps, which can be in 3D if you like, were easy to follow. The female voice that told me which turns to take sounded almost human.

Like every other navigation system I’ve tested, Nüvi gave me routes that were technically accurate, but usually suboptimal, often seriously so. My favorite example was when it tried to put me on the notorious Washington Beltway, and then a second freeway, at rush hour to get me to a point I could have reached in five minutes via a local street that was maybe 200 yards past the freeway entrance.

I was able to change these instructions by selecting an option instructing Nüvi to avoid freeways, but then it would have ignored them even when they were the best option. The Nüvi includes a clock. So, why doesn’t it, at the very least, have the brains to keep you off urban freeways during rush hour?

The Nüvi suggested different routes for the same trip on different days, and once lost its way when I emerged from a tunnel. It also had a habit of suddenly, and without notice, zooming its map view out so far that it showed the whole city, instead of my route. These examples may seem like nitpicking, but they’re fair when a product like this costs almost $1,000.

The non-navigation features worked fine, but were very basic. The music player handled songs OK, either from the Nüvi’s internal memory or an SD card, but lacked the ability to make or use playlists. The photo viewer slide shows had no manual controls or transitions.

Worst of all for such a costly device, the built-in travel guide has only sample data. To get the whole thing, you pay another $75.

As slick as the Nüvi is, I consider it too expensive for the value it delivers, at least for mainstream, casual users.

• Email me at mossberg@wsj.com.