The best mobile phone keyboard in America belongs to the new T-Mobile Sidekick 4G ($149 with contract). It’s a classic, delightful, spacious five-row expanse of letters and numbers. It easily makes the cut for our list of The 10 Best Phones with Keyboards. The rest of the phone isn’t bad, either. The Sidekick’s strongly flavored design is definitely a matter of taste, but if you like the look of the interface, you’ll love it.

Physical Design and Features
The Sidekick makes some very bold design choices, especially in changing Android’s default fonts. I’m a fan: I think it’s jazzy and it stands out, and replacing tiny icons with bold words reminds me of Windows Phone 7, in a good way. Your taste may differ.

Throw away everything you already know about the Sidekick. The old Sidekicks were generally made by Sharp; they ran a unique OS designed by Danger that mirrored everything you did onto the Web. And they had their own service plans. The new Sidekick is from Samsung, and is an Android smartphone that uses the standard T-Mobile smartphone service plans.

The Sidekick 4G is an unusual Android phone whose design tries to balance current Android technology with the classic Sidekick look. Closed, the 5.0 by 2.4 by 0.6 inches (HWD), 5.7-ounce phone has the traditional, somewhat boat-shaped Sidekick look with four buttons surrounding a 3.5-inch, 800-by-480 LCD screen, and a tiny little optical mouse replacing the Sidekick’s track ball. The four buttons are Android’s Home, Menu and Back buttons, plus a special Jump key which you can configure to create keyboard shortcuts for various apps.

Turn the Sidekick sideways, push up on the screen—don’t worry, it’s a little balky—and pow—it’s a landscape-format phone with the best five-row QWERTY keyboard you’ve ever seen. The design problem is, when you’re holding the phone sideways, the Power and Volume buttons are right where you’d naturally rest your thumbs, and they’re very sensitive. So you end up accidentally hitting them often, until you can condition yourself not to.

I can’t praise this keyboard enough. The keys are firm and clicky. There’s a dedicated “@” key, along with a dedicated emoticon key and two shift keys. The keys are all well-spaced enough that it’s almost impossible to mistype. It’s just terrific.

Phone Calls and Internet Connections
The Sidekick is an acceptable voice phone. Reception is average. The earpiece is loud, although it distorts slightly with loud inputs. On the other end, transmissions from the phone sound loud and a bit harsh or scratchy. A bit of background noise came through, but my voice was so much louder that it didn’t matter. The speakerphone is excellent—loud and sharp, with clear transmissions. The phone paired quickly with my Aliph Jawbone Era Bluetooth headset ($129, 4.5 stars) for both calls and music, and I easily activated the accurate Google voice dialing from the headset.

The phone also supports T-Mobile’s Wi-Fi calling. I tried it in several locations, and it’s very dependent on the quality of your Wi-Fi signal. With a fast, clear connection, calls sound like they’re on a cellular network, but they get choppy quickly as connections decline.

The phone runs on T-Mobile’s so-called 4G HSPA+ 21 network here in the U.S., and on 2G EDGE networks both stateside and abroad; there’s no international 3G support. Only two T-Mobile phones, this one and the Samsung Galaxy S 4G (4 stars, $199), actually support T-Mobile’s 4G speeds. The company’s other “4G” phones, the T-Mobile G2 (4 stars, $199) and MyTouch 4G (4.5 stars, $199), run at a slower pace called HSPA+ 14.4. Ideally, HSPA+ 21 should deliver speeds around 6Mbps down, although I didn’t see that on any T-Mobile devices during my testing.

The phone also supports Wi-Fi 802.11n and Bluetooth. You can use the phone as a Wi-Fi hotspot for up to five devices, with the right plan.

Battery life was a bit of a concern—I got five hours, 20 minutes hours of talk time on the 1500 mAh battery—while T-Mobile advertises 6.5 hours.

OS and Apps
The Sidekick has similar specs to a Samsung Galaxy S phone, and performs similarly to most mid-to-high-end Android smartphones nowadays. It has a 1GHz Samsung Hummingbird processor and runs Android 2.2.1, customized enough to make purists cranky. (Those folks should look at the T-Mobile G2 instead.) T-Mobile replaced some default icons with text, added some stylish-looking background themes, and changed the font under icons to something in small caps. All in all, the visual changes are sharp and good-looking.

In the first ten minutes of using the phone, though, I ran into some minor design flaws. The Sidekick’s attractive set-up app (a step beyond most other Android phones) doesn’t work properly with the keyboard open, staying rotated into Portrait mode. Just like with the unfortunate Volume button placement, this was a blip in the experience. You also have to set up Twitter and Facebook accounts twice, without any explanation as to why.

Shortcuts are a big theme here. For instance, the custom lock screen has a stripe across the middle. Drag it up, and you launch a custom-configured app—I set my lock screen to launch e-mail. Only the not-yet-sold HTC Sensation has a more functional lock screen.

The Jump key enables many more shortcuts. Where most phones have one programmable action key, the Jump key lets you have 35, launching different apps with combinations of Jump plus letters or numbers. That’s cool, and once again it isn’t like any other Android phone on the market.

Replacing the glowing “disco ball” trackball alerts, customizable red, blue and purple LEDs at the top of the screen blink different colors if you have a new text or e-mail message.

T-Mobile and Samsung have both added apps. The Sidekick-exclusive apps include group texting and “cloud texting,” which lets you manage your texts from the Web. T-Mobile dropped in T-Mobile TV, Telenav GPS (which worked well in my tests), and two apps, App Pack and Highlight, which suggest other apps you might like. Samsung added Allshare, which is a DLNA client to let you play files stored on your phone through an HDTV, and its overpriced Media Hub TV and Movie store.

Otherwise, it’s basically Android. Sure, it’s been dressed up, but any of the 100,000 apps that run on Android 2.2 should run here. That’s a far cry from the few dozen apps that ran on the old Sidekick platform. All of the standard Android components are here too, which means a broad choice of high-quality Web browsers, some of which support Flash 10.2; excellent Google and Microsoft Exchange e-mail, calendar and contact support; Twitter and Facebook apps and contact integration, and all the usual features you’d expect from a smartphone.

Multimedia and Camera
Multimedia is a strength here. The Sidekick’s media app, called Media Room, combines music playback, video playback, and Slacker Radio. T-Mobile TV delivers smooth, full-screen streaming TV channels as well. The phone has about 350MB of available internal memory and comes with a 2GB MicroSD memory card; my 32GB SanDisk card worked fine.

You can sync music from your PC using the free doubleTwist software. All the usual music formats (including OGG) play fine through the 3.5-mm headset jack or over Bluetooth. Video up to 720p HD resolution also looks good, although the phone doesn’t support DIVX (it supports the similar XVID format, though.)

The Sidekick’s camera is just 3 megapixels, and it’s slow, with a 1.7-second autofocus delay. But if you can endure the wait, it takes terrific pictures—bright and sharp, they compare well to 5-megapixel images from other camera phones. The phone takes sharp, clear 720-by-480 videos at 29 frames per second, indoors and out. There’s no flash, but I find camera phone flashes pretty awful anyway. As long as you have a bit of light, this phone is perfect for capturing your next party.

There’s also a VGA camera on the Sidekick’s front that’s designed to work with T-Mobile’s Qik video chat, but we’ve never had much luck with Qik. The company was recently bought by Skype, though, so we should see some dramatic improvements in the quality of its video chat soon.

Conclusions
The T-Mobile Sidekick 4G isn’t a Sidekick. The Sidekick was a device with a cool, simple OS and swiveling screen. That platform is dead. Instead, what we have here is a Sidekick-inspired Android phone with an awesome keyboard, a great-looking UI redesign, and the occasional sour note (that poorly placed Volume button, for one). This is the best messaging-focused smartphone on T-Mobile.

That said, our Editors’ Choice for keyboarded T-Mobile smartphones remains the T-Mobile G2, in large part because manufacturers’ additions to Android tend to be divisive, and the G2 delivers similar specs without the graphical redesign.

Compare the T-Mobile Sidekick 4G with several other mobile phones side by side.

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