Metallica, Nuff said.
Even if you think that you dont like metallica (which is insane btw) but love to play GH, then I reccomend you buy this and your view on the band will definately change. My sister, is against all things Metal....she's clearly delusional right? not so, she played this game for 1 day and now loves most of the songs and even pics up the mic to sing them!.
This game is for all intents and purposes quite difficult for the seasoned GH fan, I can do a few songs on Expert level on this title but most of them scare me down to hard mode due to the sheer length of the songs and the amazingly tricky solo's. The only bad thing I can say with this game there's no name input on quickplay mode...there's nothing like beating a friends score and watching them play franticaly to win the number 1 slot back :)
Bottom line, it's right up there with GH3 Legends....buy it you wont regret it.