Yup - while I am a GIANT AirPlay nerd, the interactions between the second screen and the main display is the big feature of this. Unless this handles "I am watching YouTube on my iPad and want it bigger" better than AirPlay (which is doubtful, as the Apple Halo is much tighter than MSFTs), AirPlay still wins that scenario, and this wins the gaming/movies/second screen world.
It's one of those "I'm living in the future" things. You're sitting there, browsing your iPad while your wife is across the room reading or whatever. "Hey honey, check this out" and with the press of a button the youtube video you want to share is on the TV, where she can see it.
