I wonder how the swipe task switching gesture interacts with games and other apps that involve swiping? I have it enabled with Dolphin (browser) and it's always a bit hit and miss whether the swipe gets picked up by the browser or as a gesture. I'm sure they can do it better than Dolphin, but still - you need it to be perfect, I think.

I love the design though - distinctive. Quite promising if they can make similarly bold designs for their phones running WP7.