GH:WT if you can stand the wait, is a better way to go. Online play, downloadable content, 85 tracks, you can use your GH3 guitar as your 2nd, 6 string bass and a full music editor. Plus everything RB has.
In comparison RB looks like a PS2 gimped crap port. But it's still a ton of fun if you don't want to wait until GH:WT releases.