Ars Technica has a nice summation of the rhythm wars, aka the battle between Guitar Hero and Rock Band for rhythm game (and profit) supremacy. So who will win? From the article:
For rock fans, picking a title could be as simple as one track or one band that tips that scales; assuming that both games are fun to play and the hardware works well enough, the track list is what will move rhythm games of the future.
It’s worth noting that Guitar Hero sells significantly more games, while Rock Band sells significantly more digital downloads. And save only the music creator of Guitar Hero, both games are near-identical in features, including separate online stores.
Personally, I prefer Guitar Hero to Rock Band (having played both extensively), because the music is more rocking, the peripherals are sturdier, and the difficulty is more challenging. Plus, it’s the original gangsta of rock video games in America.