What's the point of this? What is Microsoft actually trying to accomplish? Nexus 7 is $199, this device is $499 (or $599) and does what the Nexus 7 can do. The iPad Mini is $399 and has a better interface and isn't as confusing to use. Windows Phone 7 was a disaster, a huge flop.
As far as I can tell, all Microsoft are trying to do is force their desktop users to a mobile interface. I guess, trying to leverage their existing customer base. The biggest flaw in this attempt is that desktop consumers will simply just stay on Windows 7, get a Nexus or iPad and save $200 and the headache of trying out a worky and confusing Windows interface.