Rawk
Today I wandered into Best Buy to get some receipt reprints, and they happened to have the Rock Band demo station up. Between that and GHIII, I spent an hour there. Drums are fun, but the guitar is incredibly different than Guitar Hero's. It's thinner, the strumbar is (thankfully) not clicky, but the buttons are all just slightly raised off of the fretboard. I often found myself inadvertently holding buttons I didn't mean to, thanks to the way I hold the neck, and because of the les tactile nature, your hand can wander and get lost easily. Still, I'm sure we'll all adapt.