I don't think either is better because they're made by the same company and are made to look like competitors. That's really stupid because all the money goes to the exact same people. Besides they're the same thing
The new Guitar hero completely owns Rock band one and two. The drums are much more interesting, the gmae is customisable, online play is better, and the guitar has that cool slide pad that makes things easier if you master it. Just overall better. Rock Band is still a good game though. Xdes