so anyways...
i messed around with a kinect last night and it was weird. Played ping pong and it seemed, i don't know, sluggish. But that may be because I am used to the wii ping pong style where you just flick the controller, with the kinect you actually have to move to the ball and swing your hand.
Also played boxing, and it wasn't very fun. Didn't seem to accurately track my hands. Another thing you probably get used to and figure out, but I didn't.
Definitely has the "cool" factor. It has a camera so it can play back what you did in instant replay with the game at the same time in split screen, which is kind of fun.