So there's this company called Microsoft. Perhaps the name rings a bell. Pretty good at software, services, that kind of thing. They've spent the last five years getting absolutely obliterated on the most important software platform of our time: the mobile phone. Just obliterated, as arch competitors Google, Apple, even Palm (Palm!) have whizzed past, slipping the occasional kick in the ribs to Windows Mobile 6.5, laying in the gutter there. Bleeding pretty badly.

But it seems as if the hemorrhaging may have finally stopped.

Click to launch the photo gallery for a tour of Windows Phone 7

What's New

Pretty much everything. Windows Phone 7 is an entirely new OS, although you can trace its lineage back through the Zune family. Just like Windows Mobile 6.5 (and Android), it will be available on a wide variety of phones from different carriers worldwide. We tested the software on the HTC Surround, coming to AT&T in November, but this review will focus mostly on the OS.

What's Good

A lot. While a bit rough around the edges, WP7 feels carefully considered down to its core. Which is of immense importance. Even in version 1.0, it does a lot of things really, really well.

Creativity: Microsoft created an exceptionally unique smartphone UI. Bye bye icons and faux three dimensionality. That's a fairly brave choice, when you think about it. Even as some legacy computing metaphors start to slip away or evolve--the file, the desktop--icons have held fast. But WP7's "Live Tiles," after a brief, somewhat disorienting acclimation period, work really well. What's smart is they serve as both icons and widgets--the two core UI elements for most smartphones, which are often at odds.

Other choices are equally bold: two primary home screens serve as the only foundation; a militant adherence to text over graphics to convey choices; a new sense of scale, where the screen can always be swiped over to see more. None of these things have changed significantly in the months since the initial rollout, but for me, they made the jump from concept to practical reality with ease.

Performance: The HTC Surround I used for testing has a now-standard 1GHz chipset, and at no point did I feel WP7 was too much for it to handle. But setting aside megahertz and megabytes, it's often a poorly designed and implemented interface that's responsible for a feeling of sluggishness in our gadgets. WP7 is designed with a certain fluidity--animated twirly flourishes when you tap a tile; bounciness when the notification drawer drops from the top of the screen; a running spark that trails across the length of the screen as the standard "I'm working on it" notification. The keyboard keeps up with quick touch-tapping. The whole thing feels quick.

Integration of Services: And here we see where Microsoft can blow everyone out of the water. It's a funny feeling, scrolling down the apps and realizing that yes, all of these apps and services were created by the same company! Together at last! Zune, Office, Windows Live and Hotmail, Xbox Live--all are pilars (or "Hubs") of WP7--meta-apps for certain activities that can hold additional apps. And the main third-party service focus here, Facebook, is integrated quietly but smartly. Status updates pop up everywhere--not in your face, but just a side-swipe away. All of your contacts have their Facebook photos associated. You can write on people's walls, if that's your thing, unobtrusively from the contacts app. Individually, each service could stand up to its own mini-review, but overall, the general integration is a resounding success.

What's Bad

It's a first-run release of a major mobile operating system. There Will Be Bugs. And rough spots