Seems pretty cool, IMHO. I first learned of it a few months back when they came out with the ZombieU trailer. Was ecstatic. The concept was amazing.
Honestly though, wouldn't shell out hundreds for it. In the end it's just going to be another Kinect for Wii. (Don't get me wrong, Kinect was pretty cool. But sales-wise, no one bought it after it died down -- although this may not apply to the WiiU being that the WiiU still contains those nostalgic Mario games)
Reviews of it are also very, very 50/50.