Guitar Hero or something else?
1) Difficulty: After beating GH2 on expert with little problems, I am struggling to beat the last boss battle (Lou) on hard. The note charts are on a whole new level of difficulty, and you'll have notes coming at you that you couldn't even attempt in GH2.
2) Playability: To compensate for more difficult note charts, they are much easier to hit on this game. Neversoft allows more time for you to complete long strings of notes and HOs/POs.
3) Boss Battles: Although the first two are relatively easy, the boss battle is near impossible against Lou on hard or expert. I mean, I'm sure if I stick to it I can get it, but as someone who has mastered GH2 expert, not being able to beat the game on Hard is disheartening, if not frustrating.
4) I also don't like that theirs no co-op quickplay, I hope PSN network comes up with a patch so you dont have to unlock songs one at a time in co-op career.
This being said, the game is different, but not necessarily BAD... The set list is better than ever (wish their were a few more metal/metalcore). The songs are fun to play and challenging, making the replay value VERY HIGH. While there are some negatives, the game is still FUN FUN FUN. Once you adjust to the differences in gameplay, there is solid game. Guitar Hero veterans will revel in the ease of playing notes that would have been previously impossible. I will describe this by saying that your playing would look much more impressive to an on-looker in GH3 as compared to GH2.
For multiplayer, I'd like to try the battle mode. I think a lot of people dislike it from playing Lou and getting owned. Against other humans, I see some potential. Overall, I'm satisfied with my purchase. Although the game is different from the others in the series, it's still good fun.