Rockband because you get to play better songs and a better style of the notes, not circles. But yeah! Squares. And I know Guitar hero got it too but they copied and made it just horrible. That rock revolution game is horrible!
Guitar Hero Pro's: Solid Equipment and Hard songs. Also for GH:WT Song Creator and and Sharing. Con's: Just not as many songs as rock band
Rock Band Pro's: Like i said, Rock Band has Hundreds of downloadable songs Con's: Unsteady Equipment, and downloadable songs run for 80 MSP, most for 180 MSP, Packs for 440, and 1200's will take a chunk out of the wallet.
I go with GH since it came out.. and i will be getting World Tour soon =)
See I have to say the Guitar hero is better for partying with mates, probably because mine are such GH fanboys. But I only got rock band recently and I'm not sure but it could be more fun. XD