The 5800, which features HTC's very cool sliding QWERTY keyboard, is a good example. It's a Bluetooth-enabled Swiss Army knife of a CDMA1xEVDO smartphone. It runs Microsoft's new Windows Mobile 6 Standard Edition operating system.

Qwest is currently selling it as the Qwest Fusion HTC 5800 for $200 - $200 off the regular price, the company says - with a two-year contract that includes up to 2.9 hours of talk time. Data contracts range in price from $20 (35MB) to $40 (100MB) a month and $1 per MB over.

Bell Canada also has the 5800, for as little as $150 with a three-year contract on which you guarantee to spend at least $45 a month - or as much as $450 with no contract. I reviewed the Bell product.

Verizon Wireless says it intends to start offering the HTC 5800 soon.

The 5800 is a gem and performed well in most functional tests, but it's a little shy of perfect.

In terms of hardware, this is a middling powerful smartphone. It uses the 400MHz Qualcomm MSM7500 processor and, according to HTC, comes with 64 MB RAM and 256 MB flash ROM. The Bell version, in fact, only has 128 MB of flash memory. All versions also have a microSD slot. (1GB microSD cards sell for about $20, the largest-format 6GB cards go for about $90.)

The form factor and interface are among the 5800's most appealing characteristics. This is not the smallest smartphone on the market, but must be close to the smallest with a full QWERTY keyboard. It measures just 4.1 x 2.0 x 0.7 inches (103.5 x 51 x 19 milimiters) and weighs 4.2 ounces (120 grams).

Unlike the similar HTC P4000, a WinMobile 5 device that we reviewed earlier this year, the 5800 has a number pad on the front face as well as the QWERTY keyboard. Not surprisingly, the 5800's bright 65,000-color screen is a little smaller as a result, but not much—2.4-inch versus 2.8-inch for the P400.

One downside: no touch sensitive screen (it is a Windows Mobile 6 Standard, not Professional device, after all), no pen-based control or input. So if you're a stylus-centric kind of smartphone/PDA user, this model is probably not for you.

Below the screen (when viewed in portrait mode) is a five-way navigator (left, right, up, down, OK) and two soft keys that change function according to context. The green Talk and red End keys flank the numeric keypad, which can be used to input text as well using the multi-press technique. There are also dedicated Home menu and Back keys below the number pad.

There's a dedicated button for activating the camera, on the right-hand edge, and a volume up-down slider and power button on the left side round out the hardware controls.

When you slide the QWERTY keyboard out - to the right, as with the P4000 - the screen automatically switches to landscape mode. The keys are of course tiny, but they're well shaped and raised just enough so that you can type fairly quickly using thumbs, cradling the device in both hands. The most frequently used special characters, including the all-important @ sign, are easily accessible using the function key.

HTC also includes word completion software that works well and learns often used words, so you rarely have to type entire words.

The 5800 offers an array of hardware-based capabilities, including the already mentioned Bluetooth, that have by now become almost obligatory in smartphones. The video-capable digital camera has a resolution of 2.0 megapixels. It has no built-in flash, however, as many phone cameras now do. And although the documentation says it has a zoom function, this feature did not work on the unit I tested. (No matter, digital zooming is pointless anyway.)

I am not a great user of or believer in phone cameras, but I appreciate that others find them useful - or at least fun. This one performs no worse than most I've tried, and better than some. Focus, as with all fixed-focus cameras and especially phone cameras, is soft. But exposure controls and color rendition appear better than with many phone cameras.

The voice dialing feature, which HTC correctly calls voice speed dial, is not the easiest to use. It requires you to create a voice tag —a recording of you saying a short form of a person's name—for each contact you want to dial by voice. Some other voice features I've tried let you dial by speaking the name of any contact in your list—although they may not interpret the name correctly 100% of the time.

There is also no dedicated button for activating voice dialing, as there is with many smartphones that offer this feature. It takes about three clicks, going through the Windows Start menu, to activate voice dialing - which seriously reduces its utility in my opinion.

Windows Mobile 6 introduced some potentially important software improvements, including Outlook Mobile, which delivers full HTML mail with pictures, formatting, etc. intact. The Office Mobile suite, handheld versions of Excel, Word, Powerpoint, is now a standard component in the operating system, and the applications are improved over past Pocket versions.

It also provides better support for calendaring and introduced Windows Live for Windows Mobile, an online portal providing access to Microsoft's free software-as-a-service (SaaS) messenger, contacts, mail and search applications.

ActiveSync, Microsoft's synchronization utility, has been improved. It worked flawlessly with the 5800 and synched my enormous contact database much faster than past versions. That said, I did have to uninstall a previous version of ActiveSync and reinstall the version that came with this product before it would recognize the 5800.

The mail experience, a crucial consideration for many users, is little different from past Windows Mobile devices. This is not the vaunted push e-mail that the platform supports if you're using the device to connect to a Microsoft Exchange Server—and which Microsoft is leveraging in the enterprise market to make serious inroads on the RIM BlackBerry's market share.

Some mobile operators are partnering with companies such as Visto to provide non-corporate customers with push e-mail service, but Bell, at least now and with this product, is not one. You can set up multiple POP3 and/or IMAP mail accounts and, as with POP3 accounts on the desktop, tell the messaging application to check for mail as frequently as every five minutes.

The application doesn't, by default, download the entire message, but it does get enough in most cases that you won't need to download any more until you get to your desktop.

Windows Mobile 6 attempts to detect your e-mail account settings automatically. It didn't work when I tried to set up my main POP3 account. Windows Mobile assumed my address was an IMAP account, set it up accordingly and then, naturally, couldn't connect. It also wouldn't let me simply modify the settings. I had to delete that account, start over and use the manual set-up option.

The 5800 offers little in the way of software beyond what is included with Windows Mobile. A picture and video viewer is about all.

On Bell's EV-DO (3G_ network, surfing using the Internet Explorer Mobile browser was very quick indeed. Web videos even played okay, in some cases, sort of. When I watched movie trailers at Microsoft's WindowsMedia.com site in 'Hi' (bit rate) mode, the images were clear and reasonably sharp, but motion typically degraded to a slide show. In 'Lo' mode, the video moved, if a little jerkily, but images were fuzzy and pixilated.

This is mainly a bandwidth issue, of course. Given a little more—the smartphoen reported bit rates as low as 28 Kbps at times while it was streaming video —this device could, I'm sure, play video quite well.

To make a voice call - which is what these things are mainly for, remember - you simply dial the number on the front keypad. On the assumption that you may be trying to dial by name using the multi-press number pad entry method, the HTC dialer also presents matching names from your contacts list. To me, it would make more sense to find records with telephone numbers matching your input, but maybe that's just me.

In my voice call testing on the Bell network, audio and connection quality were consistently excellent.

Bottom line: This is a powerful, full-featured smart phone selling at a pretty good price—although, as always, only if you sign up for a multi-year contract.

Its main differentiator is the sliding QWERTY keyboard. If you're not sure you will get maximum benefit from it—if you don't expect to be composing a lot of text messages or e-mails—there are lots of other models that are equally deserving of attention. If you see the keyboard as providing an important benefit, the 5800 should be at or near the top of your list to investigate.