Guitar Hero 2, is a exciting game.
And frankly one of the few you find yourself playing for 3hours straight with friends. Its extremely addictive game play, might even take you a couple days to master the easiest level. Now as a actual guitar player and if you are too; Do not expect it to be even close to the real thing.
Yet still, you'll find yourself playing the next song and the song in no time. (or just repeating an old one thats getting you frustrated...) Given that its semi-old now, with Guitar Hero III, its still worth the time to go and buy.