Aside from the official Microsoft announcement in February and the steady stream of leaks and rumors that followed, it’s been fairly quiet on the Windows Phone 7 front of late. And other than the HD2 and the LG Fathom, 2010 hasn’t exactly been a banner year for Windows Mobile 6.5 either.

But this week marks a milestone in the Windows Phone 7 journey.  Now, for the first time, reviewers and developers have prototype Samsung smartphones running a near-final version of Windows Phone 7 in their hands.  And that means, among other things, that Windows Phone 7 will quickly shift from chatter and conjecture to any-week-now reality.

Engadget, Boy Genius Report and SuperSite for Windows have each posted first impressions of the Windows Phone 7 OS based on experiences with the prototype devices.  The response is mixed, as you’d expect, and each source highlights aspects of the OS that delight, confound and disappoint. 

If you’re interested in Windows Phone 7 – and if you’re reading this, you very likely are –take a look at the posts and judge for yourself what you think of Microsoft’s upcoming mobile reboot. 

The first smartphones based on the operating system are scheduled for release in Q4 of 2010, so it’s crunch time. 

UPDATE: TechCrunch, ZDNet and Gizmodo have also posted preview pieces.