In a nutshell Microsoft’s SmartGlass app is what Apple’s AirPlay could be if Apple played well with others. MS making SmartGlass available on all mobile devices (wait, no WebOS love?) is huge and a sign that MS is realistic enough to know that it needs to look beyond itself in order to succeed. If SmartGlass only worked with Windows products it would be a bigger flop than Zune.
I’m not sure how well of a game play companion SmartGlass is going to be, but it’s the home media applications (coupled with MS’s new content announcements) that has my attention.