A really, really, really fun game.
A beginner can play songs at the beginner level and gradually become better and better, so there is no one that won't be able to play a song.
This game manages to bring together many people at once to play this game. Its a great multiplayer game, either for tournaments, or just a 1vs1. It can get pretty intense. My only complaint is that some guitars I have played on have not responded to the wireless connection and the buttons on the guitar sometimes stick if you play with them A LOT.
But other than that this game is amazing and can keep you addicted for hours. Days. Literally.