I beat all the songs with three stars or more on both Easy and Medium modes. I've also played the last couple songs on Expert mode at my friend's house as well as played in a tournament with my friends. I've beaten as much of the game as I care to.
Got this from Gamefly shortly after Christmas time, ended up beating Expert career on guitar on the 30th. Didn't take me very long. I failed "Train Kept A Rollin'" the first time; I wasn't expecting it to be that hard after playing it on Rock Band. I can safely say this is the worst GH game I've ever played.