I had a few moments to spend with the freshly announced Windows Phone 7 Series operating system. One thing is clear: Microsoft is serious about taking back the smartphone crown. With OEMs and network operators on board, Windows Phone 7 is its biggest -- and riskiest -- step yet.Microsoft was exceedingly stingy with the number of prototypes it had on hand with Windows Phone 7 Series on board. Despite their scarcity, I had a chance to spend a little time with the new operating system.

In the few moments I had, I came away impressed. If you considered Microsoft to be down and out, it's definitely back in the ring, both gloves laced up, ready to fight. The user interface has been minimized and shrunk so that many of the annoying elements of Windows Mobile 6.5.3 and back are eliminated. Everything is just a few taps away no matter what app you happen to be running.

Screen transitions are fluid and smooth. I like the animations. Microsoft is definitely headed in the right direction with its highly integrated "People Hub," which lets people see various bits of information from their contacts.

The new "Music & Video" and "Photos" hubs are fantastic re-realizations of how media should be consumed on a handset. I especially like the way photos are shared across applications, so that when you view a contact, you can see their recent picture uploads. The Photos hub also pieces together recent uploads and images to create galleries on-the-fly.

The messaging, calendaring and PIM tools are solid and will let the business user handle the basics.

Here is a short list of pros and cons that I can think of off the top of my head.

Pros Brand new, from-the-ground-up operating system and user interface. Great mix of social networking and PIM management. Zune music/video integration a huge step forward for Microsoft's mobile experience. Much better treatment of photos and media. Simplified menu structure. Only three buttons to worry about. Multitouch is included. Bing search is voice-enabled and powerful. Cross-integration of data and apps creates great ways to interact with content. Vast number of handset makers and network operators on board to deploy. Huge ecosystem for support. Looks polished, and fast.

Cons Long time to market (4Q10). No backward compatibility with previous WinMo software AT ALL. No clear developer benefit. Fonts are annoying. UI is a little bit stark. No multitasking. No Flash. May still not appeal to customers. Definitely won't appeal to business users from the onset, despite Microsoft Office and messaging support.

Here is a really cruddy video of the new UI in action. Honestly, it was the best I could do, given Microsoft's complete control over the demo units.