Now that Activision has announced that RB peripherals will work with GH:World Tour, we'll probably get that one, too. Just to play some of the stuff we like that RB doesn't have. I'm sure we'll still far prefer playing with RB.
Looks like there may be a couple of tracks that won't be able to be exported from the RB 1 disc due to licensing issues. One of them has to be "Train Kept A Rollin'" - not really a loss at all in my eyes.