I enjoy the games, they're a different sort of challenge to your usual video game (no fighting bosses and stuff like that) and most games don't actually challenge your dexterity or co-ordination whatsoever. I know it's nothing like playing an actual guitar/drums/whatever, but it's something nice to chill out and play every once in a while. I mean, like mingot said, it's so easy to pick up and play (if you're remotely competent) and you don't have to worry about tricky stuff like you do when playing an actual instrument.
My favourite Guitar Hero game is World Tour, since it has the best song list I reckon. Nothing matches the three Tool songs on World Tour on any other Guitar Hero, along with a few other songs in particular.
What I do not like about Guitar Hero is people forming opinions of a band based on the songs floating around on the game. I mean, I like Shiver, and that made me download Coldplay because maybe they weren't as crap as I originally thought, but turns out they are. But if I heard Shiver and said "fuck yeah Coldplay are awesome" I'd have to call myself a (BAN ME PLEASE).
It made me also check out Lacuna Coil (who are awesome) and probably a few others who I don't remember. It's quite good to find a few bands, since a few of the songs were by bands I'd never even heard of before, which was good and bad. Also it gave me increased appreciation for the bands since I was playing, say, Schism on bass and was thinking throughout the song "how the fuck do Tool play this song with actual instruments", it gave me much more respect for their skill.
Man this post is long for no apparent reason.
Also I play bass on Hard usually, but can do Expert on some songs.
