Nokia Lumia 810
T-Mobile's Nokia Lumia 810, isn't an immediate knockout. Its thick, heavy, slablike form is hard to love. But since beauty is only skin-deep, T-Mobile customers will find hearty hardware and software features within. All things being equal, I prefer AT&T's Nokia Lumia 920, which is both more powerful and also easier on the eye (although it's a full ounce heavier).
That said, the Lumia 810 does have a very nice screen, an 8-megapixel camera, a zippy dual-core processor that's identical to the Lumia 920's, and a host of extra apps. The Lumia 810 is also pricier than the heavily subsidized $99 Lumia 920. However, it's still less expensive than the much more attractive-looking HTC Windows Phone 8X, which is also available on T-Mobile for $199. Pricing gets a little funny for the Lumia 810.
On the Classic plan, the 810 will cost $149.99 after a $50 mail-in rebate on a two-year agreement. T-Mobile's Value plan is the better deal, $99 up-front after a $50 mail-in rebate, and 20 equal payments of $20 per month, but with lower monthly payments over the course of two years. You'll save about $100.