Some will say the Windows Phone 7 (WP7)-powered Lumia 710 is an underwhelming vehicle for Nokia’s re-entry into the U.S. smartphone market. However, after spending some time with this, the lower tier of Nokia’s first two WP7 phones, I was as pleasantly surprised with this mid-ranger as I was with the Lumia 800, although my expectations were lower for the 710.

Launched today as an exclusive on T-Mobile USA’s network, the Lumia 710 is available for $49.95 with a two-year contract. While that $49.95 price tag screams mediocrity, the 710 offers far more polish than what you’d see in an “affordable” mid-range Android smartphone.

Hardware
This isn’t the Lumia 800. There’s no curved gorilla glass touchscreen and there’s less of a solid, cohesive feel to this device than you’ll find in its more expensive counterpart. Nevertheless, there’s little to complain about.

The Lumia 710 is lightweight, with a rubberized back plate and minimal physical buttons. Along the right side are the volume toggle and power button. Mini-USB port, headphone jack and power button are all at the top. Back, Home and Search buttons are all included in a single physical button at the bottom of the phone. I wasn’t a fan of this combination button, as it was hard to press. I’d rather have seen this as either individual physical buttons or touch buttons.

Aside from that physical button at the bottom, my only real gripe with the hardware here is the 3.7-inch ClearBlack WVGA scratch-resistant capacitive touchscreen display. While it may be scratch-resistant, it’s most certainly not fingerprint resistant. After even moderate use, the display on this phone was all gummed up, and this was not because my hands were exceptionally dirty.

Specs
The specs here aren’t exactly going to set the world on fire, but they’re also a little above average for this class of phone. The 710 features a 1.4 GHz Snapdragon processor, which renders the WP7 page transitions and live tile animations with almost no lag. I have to admit that after using the iPhone, which has a more a static feel, the frenetic environment of Microsoft’s platform is a nice change.

The 710’s 5-megapixel camera is also quite good and includes autofocus, LED flash, 4x digital zoom and 720p video recording at 30 fps. There’s also native shooting modes, which include panorama, “scenes” and image effects. Shutter lag was almost non-existent and the camera did well in low light situations.

As far as storage, it looks like Nokia will take Apple’s lead and nix the SD cards for expansion. The 710 comes with 8 GB of on-board storage, as well as a complimentary 25 GB of cloud storage on Microsoft’s SkyDrive.

The Lumia 710 is a Quad-band GSM, UMTS phone (Bands, I, II, IV, V) and T-Mobile is calling it a 4G device. In this case, 4G means HSDPA, with theoretical peak download speeds of 14.4 Mbps. There’s also Wi-Fi 802.11 b/g/n and Bluetooth.

Apps and Content
According to a recent report from All About Windows Phone, Microsoft’s Windows Phone Marketplace has hit 50,000 app submissions, with 13,000 different publishers submitting over 17,000 apps in 90 days. Those numbers are a major coup for Microsoft’s budding platform.

As a closed system, WP7  provides developers with a standardized look and feel, which in turn translates to a more predictable and enjoyable experience for the end user. Apple is a great example of this approach, and WP7 is not too far behind iOS in the UI department.

While Netflix comes preloaded on the Lumia 710, as well as T-Mobile’s mobile TV app, Microsoft still needs to think about adding a more cohesive multimedia ecosystem, where music and movies can be purchased from the handset, without having to connect to a computer. Apple has led the way in this area, and Android should be thanking Amazon for what it has done in the way of content availability for Google’s platform.

Microsoft isn’t there yet. Certain big name apps are still absent from Windows Phone Marketplace that some users won’t be able to live without if they’re coming to WP7 from another operating system. However, Microsoft has attracted a number of big names (Angry Birds, ESPN) and with 50,000 submissions already, momentum seems to be on its side.

Questions, Comment, Concerns
Windows Phone 7 is the closest thing to an iOS competitor that I’ve seen, but too few consumers actually know about it, which at this late stage of the game could spell trouble. Going forward, Microsoft and Nokia need to come up with some serious marketing ideas for their smartphone business, which is to say that they need something gaudy and attention-grabbing that’s in line with the campaign for Verizon Wireless’ Droid franchise.

My biggest concern when the Lumia 710 was announced back in December was whether Nokia could afford to return to the U.S. market with less than its very best. In the end, I think they did the right thing. At the nicely subsidized price of $49.95, the Lumia 710 is the perfect test run for the inevitable launch of an exclusive, high-end flagship phone in early 2012, most likely on AT&T’s network (CES?).

The Lumia 710 isn’t going to let anyone down; in fact, it may surprise some, but most importantly, it gets Nokia hardware running WP7 in the hands of consumers at a reasonable price.

I might even throw the “game-changer” label on the 710. At $50, it raises the bar for what the end user should expect from a mid-range smartphone in the way of specs, usability and quality. Unfortunately, the question is whether anyone in North America actually noticed that Nokia and Microsoft are back in the game.