This is the best fun rocking game ever! Everyone should play, it's hard at first but once you get in rhythm, it's fun!
But, more I played it, more I get better, it's fun if you keep playing it and plus it does help my left hand to get some exercise it needs. Most of my favorite rock songs are on there and I really love the game, especially my 6-year-old cousin plays it awesomely well.
The timing may be hard, but you gotta practice, practice, practice 'til you get better at it. Guitar Hero II is a good game, but I could recommend by rent it with the guitar controller BEFORE you buy it.