So I got Rock Band yesterday. Finally able to find it in the city. Spent 9 hours playing the drums with my friends and my ankle hurt so bad I had to stop.
Lead guitar is rediculously easy for the most part (But that's coming from me. It's probably not that easy for you), Bass is easy as always in most songs, but it can have a x6 multiplier. Drums are fucking hard (I play on hard. below that is fairly boring) but my favorite by far.
Of course the soundtrack is pretty awesome. Except for the inclusion of Nirvana again. Makes me sick. Also Fall out Boy deserves to die. Otherwise great.
The best part for me though is how much effort goes into making "your" band come alive. The loading screens use your custom made characters, and the drumming animation is far more impressive than in GH3. Plus you aren't forced to use some random douche for a singer/bassist/drummer as long as your friends are there to play too.
But the whole point of this is that now I have a working guitar to use with GH3 again! Hooray!