Actually, if I had to get a Rock Band game, it would be this one. Firstly, because I don't know any of the Beatles songs except perhaps Yellow Submarine (which is because a bunch of kids from my old troop used to sing it on a regular basis), secondly, because I don't like mainstream music nowadays... Enya, Evanescence, Within Temptation, Hans Zimmer, all manner of VGM remixes... what do they have in common? None of them play on the radio (well Evanescence has "Call me when You're Sober" and "Bring me to Life" on the radio, but those are not their best songs by a long-shot).
Beatles comes from an era where mainstream music did not involve a bunch of teens singing cheesy lyrics, a girl trying to blur the line between a music video and a, well,
you know what I mean, and a bunch of bad voices trying to hide their lack of talent behind really, REALLY loud electric guitar.
Beatles just feel more wholesome, which is more than I can say about any Guitar Hero or Rock Band group I've seen thus far, so I may actually consider this game if I had the money for it.