Ars Technica reviews:
Nothing about the music in this game was done the cheap or easy way, and it shows. You can set up a custom mix of tracks and then just sit back and listen to the music without having to play, or use it as the background music for a party while the game displays visuals on your television if you just want to enjoy the tracks themselves.
And check out the controller:
Wicka-wicka-wicked: DJ Hero new, fresh, triumphant – Ars Technica