This week, I'm continuing my obsession with--whoops, I mean my "reporting on"--ultraportables.

During the past few weeks, I've compared notebooks on PC World's Top 5 Ultraportable Laptops chart to their bigger brethren on our All-Purpose and Power charts. What I discovered is that the best ultraportables aren't far behind the best all-purpose and power laptops in terms of overall quality and performance. But ultraportables are pricey, and they can weigh nearly as much as an all-purpose laptop, once you factor in an AC adapter and other peripherals.

In last week's column, I reviewed the slick, stylish Sony Vaio VGN-TXN15P/B. My assessment: It's a pricey but compelling ultraportable for folks who don't mind a smallish screen and keyboard.

Now, the last chapter in the saga (for now, at least): a look at Fujitsu's LifeBook P1610, an ultra ultraportable with a swiveling, tablet-style screen. As with the Vaio TX, I've given the LifeBook P1610 a grade from A through F for size; screen; keyboard; features; battery life; and price.

By the way, my colleague Melissa Perenson recently reviewed the LifeBook P1610 as well.

Size: Extremely Compact

Weighing 2 pounds, 3 ounces (according to my digital postal scale) with a standard 3-cell battery, and measuring 9.13 by 6.5 by 1.4 inches (according to my tape measure), the LifeBook P1610 is roughly the size of a standard hardcover book and not much heavier. Even with an AC adapter added, the combined weight is still under 3 pounds.

However, the notebook lacks a built-in optical drive. Fujitsu's external dual-layer DVD writer ($269) and its AC adapter weigh 1 pound, 11 ounces, bringing the total travel weight--including notebook, DVD writer, and their AC adapters--up to 4 pounds, 9.7 ounces. That's still svelte, but it's nearly a pound heavier than the Vaio TX notebook (which has a built-in optical drive) and its AC adapter, with its combined weight of 3 pounds, 8.9 ounces. Grade: B

Screen: Designed for Touch, Indoor/Outdoor Use

The LifeBook P1610's 8.9-inch touch screen swivels into tablet mode. You can even use your finger as an input device (some tablet PCs require a special stylus for touch screen input). The unit I tested came with Windows XP Professional, though Fujitsu also offers Windows XP Tablet PC Edition 2005 as an option.

The screen features a coating that makes images and text legible in outdoor as well as indoor lighting. If you're looking for a portable to take to the park on a sunny day, this one's a good candidate.

The screen's native resolution is 1280 by 768 pixels, which makes the icons and system fonts extremely small. Folks without 20-20 vision will get all crinkly around the eyes from squinting. The notebook delivers up to 1600 by 1200 pixels to an external monitor, however. Grade: B+

Keyboard: Not for Fat Fingers

According to Fujitsu, the LifeBook P1610's keyboard features a 16mm key pitch and 2mm key stroke. In comparison, a standard QWERTY keyboard has a key pitch of 19mm and vertical key travel of 3mm to 4mm. The result: You could end up with some achey-breaky fingers after typing on the LifeBook P1610 for an extended period of time. Grade: C+

Features: Limited But Good

The LifeBook P1610 provides a basic set of features that will serve most users' needs on the go: 802.11 a/b/g and Bluetooth wireless connectivity; two USB 2.0 ports; headphone and line-in jacks; RJ-11 and ethernet ports; a VGA port; a Secure Digital card slot; and a PC Card slot. As I mentioned earlier, there's no built-in optical drive. But other than watching movies on a plane or installing software, how often do you use one? Grade: B

Battery Life: Fair

I didn't rigorously test the LifeBook P1610's standard 3-cell battery. But I can say that after 2 hours of continuous use, with wireless connectivity on and no power-saving features enabled, the battery had 13 percent capacity remaining. My guess is you'd get 2.5 to 3 hours or more from one charge, depending on if you're using a wireless network. Grade: C-

Price: Expensive

The LifeBook P1610 I tested came with an Intel Core Solo Processor Ultra Low Voltage U1400 (1.20 GHz, 2MB of L2 cache); 1GB of system memory (which can't be expanded); and an 80GB, 4200-rpm hard drive. That'll cost you $2419 (though there are bargains online). If you add the optional DVD writer, the total is $2688. That's a lot of money for what you get, in terms of specs. But no one (certainly not me) ever said ultraportables are a bargain. Grade: C

The Bottom Line

The Fujitsu LifeBook P1610 is a well-designed, extremely compact, and flexible notebook.

Anyone who roams around a lot during the workday and needs continual access to a computer is an ideal candidate--particularly if price isn't a big concern. If you frequently spend some of your work day outside (for legitimate reasons--or not), you'd probably find this little computer invaluable, too.

Otherwise, a full-featured ultraportable, such as Fujitsu's LifeBook P7120 or Sony's Vaio TX series, is probably a better bet.