I was a little skeptical of the track list, but it's actually really good. Some of my favorite picks are "Carry On Wayward Son" by Kansas, "Man in the Box" by Alice in Chains, "That's What You Get" by Paramore, and "The Middle" by Jimmy Eat World. Some of the songs aren't what you'd expect from a Guitar Hero perspective, but then this is Rock Band, and not Guitar Hero.
The guitar, bass and drums are all a lot of fun, but I didn't find the vocals to be quite as enjoyable, mostly because I'm not that familiar with a lot of the songs. Sure, they have the lyrics at the top of the screen, but they can be pretty hard to follow, especially if you don't know the song. You don't really need to be a proficient vocalist either, you just need to go higher and lower in pitch at the right moments to get a good score. Not to say that there's anything wrong with that.
This game is a must-buy if you like to play video games with your friends. At the end of the day, it's just a game and it's as much fun as you make it.