As a lifelong DDR fan I was skeptical of new dance-game technology. But Harmonix has done a pretty solid job in taking advantage of the Kinect technology (Xbox). The Kinect itself reads moves pretty well - the game is sensitive enough to know when your form is poor even if you are hitting the right moves.
The songs are pretty awesome and there are plenty of neat moves, but I have a couple of complaints. One, that the training stage only shows you the move ONE time before you are expected to be able to repeat it - and some of these moves are pretty intricate. Two, that there is a ton of "yea boyeeee that's what i'm TALKIN bout" crap as the dancers trash talk each other, and you can't skip over it. It's a lot like SSX post-race. I miss DDR's crazy mode where you'd do a ton of songs back to back.
Overall - great workout, entertaining game, solid technology that doesn't confine you to a ddr pad.
Rating: A-