GH4.. Rock band has no advantage now. lol.
I highly disagree. Unless they can manage to sign alot of more bands, a cell-phone ring tone quality studio mode cannot catch up to the number of songs RB has. At this point, they're more evenly matched. GH:WT has creativity (Though IMO, studio sounds horrible but they had the right idea going and it was good on paper) and RB has a large song-base.
I also noticed GH:WT is a bit more challenging to drum players, but lacks vocals alot, as I've seen many videos where the vocalist does nothing at all.