I've played an hour of the game last night and I'm really enjoying it!
Had the game been pad controlled, it would lose a lot of it's appeal. It would end up being a so-so melee zombie game. I've found the Kinect controls to be responsive, the story to be very House of the Dead inspired and the actions have a good variety and are intuitive. My only complaints: no other play modes outside of story and from what I hear it can be a short playthrough. So $50 might be a bit too expensive, still it has the same amount of gameplay as any SEGA lightgun game, but has far more freedom in terms of actions and movement. Review to come...