all games are not created equal

DJ Hero is a clear win on this one.  I never had fun playing GH by myself; it's just meant to be played with other people.  DJ Hero isn't like that though.  It's actually almost the exact opposite, where group play isn't really worth it. 

DJ Hero is a ton of fun to play and it's one of the only music simulations that actually made me feel like I was controlling the music and not just playing along.  GH is still cool, but just doesn't connect to the music nearly as much as DJ Hero does.

DJ Hero is also pretty challenging in a very new way, which is extremely refreshing given how long guitar controllers have been around. 

Biggest point against DJ Hero though is that it's pretty expensive.  Despite the price point, I still am glad that I bought it and will continue to enjoy it down the road.