The Good: Thanks to its Windows Phone 7.5 Mango OS, Nokia's Lumia 710 provides plenty of power for both fun and productive uses. It has a smooth and engaging user interface, satisfying photo quality, and 720p HD video, all in a compact and affordable package. The Bad: The Lumia 710's all-plastic construction doesn't scream luxury and its small physical buttons are stiff and often tough to press. The handset also lacks a front-facing camera, so video chat is out of the question. The Bottom Line: The $49.99 Nokia Lumia 710 is an excellent way to get the growing capabilities of a Windows Mango smartphone for a rock-bottom price. Though it isn't an Android superphone with a luscious AMOLED display, it's a practical device that covers all the mobile bases. Editors' note: The following review evaluates the Nokia Lumia 710 on T-Mobile. Please note that performance on the unlocked version of the Lumia 710 may vary in terms of data speeds and call quality, compared with the version of the phone that is optimized to T-Mobile's network. \n\n\nNeed a modern smartphone choice on T-Mobile but aren't willing to spend the hundreds of dollars usually required? Perhaps you should take a gander at Nokia's new $49.99 Lumia 710. With strong features for work and play, plus a 4G connection, it could become your new mobile best friend.\n \nDesign\nSure, it lacks the playful colors and personalized back plates of its European cousin, but the U.S. version of the Nokia Lumia 710 shows some flair of its own. It comes in two main colors, all-black like my review sample, and a model that sports a frosty white front.\n \nCrafted from unassuming plastic, the Lumia 710 looks pretty mundane aesthetically at first glance. Once you pick up the 4.4-ounce handset, however, it's clear that it's solidly made if not luxurious. Measuring 4.69 inches tall by 2.46 inches wide by 0.49 inch thick, the compact device sports attractively rounded edges and fits into tight pockets without too much trouble. The phone's back cover has a rubbery, soft-touch coating, too, which provides a sure grip.\n\nOn the front is the 3.7-inch (WVGA, 800x480-pixel resolution) LCD screen, which is smaller and not as sharp as the full-HD or even qHD displays boasted by higher-end Android devices. Also, though it lacks the fantastically deep blacks and eye-popping colors of other devices with AMOLED displays, namely the , Galaxy S II, and , or even the original Focus, it does serve up pleasing-enough image quality.\n\nThat said, Nokia adds its special ClearBlack technology to boost screen contrast. For instance, I had a great time watching the YouTube HD trailer for "The Avengers," which boasted plenty of rich eye candy like bright fiery explosions, energy blasts, flowing capes, and Scarlett Johansson's artfully arranged red hair. Also, the Lumia 710's screen had noticeably darker blacks than the display on the HTC Radar 4G, which tended to leak some light around the edges.\n\nHandling typing duties is the standard Windows Phone virtual keyboard with square, blocklike keys pressed closely together. Most buttons don't double as punctuation marks, though long-pressing the period key pulls up a selection of often-entered symbols. Additionally, like all WP7 phones, the Lumia 710 doesn't have the option of haptic feedback. Despite this, my typing experience was comfortable and I easily and quickly banged out messages and e-mails. \n\nAbove the display is a nondescript earpiece and below it sits a thin, flexible bar that serves as three buttons for Back, Windows Home, and Search. While I usually like physical keys, I found these buttons stiff and often hard to press. The same goes for the tiny volume rocker and dedicated camera button on the phone's right side and the recessed power key located on the Lumia's top edge. Also on top are a standard 3.5mm headphone jack and Micro-USB port.\n\nPlaced on back are the 5-megapixel camera with LED flash and a large speaker. Ripping off the handset's battery cover reveals its 1,300mAh battery, which you need to remove to access the phone's SIM card slot. At least the battery is removable, unlike the HTC Radar 4G's, which is locked in by that phone's fancy unibody metal chassis. \n\nFeatures\nThe Nokia Lumia 710's Windows Phone 7.5 Mango interface is virtually identical to that of other WP7 devices I've used. That's to be expected, since Microsoft lays down strict rules for how Windows Phone runs on mobile handsets. I'm not complaining, though, since my familiarity with Mango had me up and running in a matter of minutes. For those who don't use the Windows Phone operating system often, the home screen, called the Start Menu, consists of Live Tiles arranged vertically. Functioning the same way app shortcut icons do in Android and iOS, Tiles also behave a bit like widgets, pulling in data and displaying information in real time. \n\nFor instance, Messaging, Email, and Gmail Tiles showcase the number of new messages, while Pictures will flip through your gallery highlighting snapshots. Swiping left opens the main menu with a full list of installed apps. You can also pin apps and other things like picture albums and videos to the home screen for fast access. A People Tile taps into social media networks like Twitter, Facebook, LinkedIn, and Gmail accounts to populate your contact list and provide live updates. Overall, it's a very slick and engaging UI rendered in a clean, modern font.\n\nHere too is access to the Microsoft Marketplace app store, which has a much smaller selection than the iOS and Android storefronts but does feature many of the software basics, such as Facebook, Foursquare, Twitter, and Tripit, just to name a few. Nokia and T-Mobile pre-install some useful titles too, specifically Netflix so you can stream movies on the go, the Weather Channel app, and Nokia Drive for free turn-by-turn GPS navigation. Of course, if you'd rather pay for directions, the TeleNav GPS Nav app costs $9.99 per month.