Worth playing, but a little overrated for a few reasons.
My biggest complaint is the Fender strat controller. It is a flat out atrocity, and I've never been able to comprehend why some people like it. The flat buttons, while more realistic, make the game totally unplayable, so I always use my old Guitar Hero controllers despite them not having the bottom buttons for guitar solos (that is the single benefit of the Fender controller). The strummer is even worse, as it's so fluid that you can't even tell when you're strumming, whereas other controllers give a little resistance (simulates actual strumming a little more closely).
The game itself is not without its faults, either. As with every Harmonix game I've ever played (including Guitar Hero 2) Hammer-ons and pull-offs seem to only work when they want to, regardless of what controller you're using. This problem has improved compared to the original Rock Band, but it's still bad. Also, when you're in a part where there's repetitive strumming of the same note and you miss one note, you seem to miss several notes after it despite totally strumming at the correct time. I've tried calibrating dozens of times, doing it with no calibration, same thing still happens (and doesn't in newer GH games). Also, you have to play the same songs multiple times throughout the tour in this game when they have the multi-song sets. Those multi-song sets are boring, and seem to only be there to try to make the game seem longer.
On the bright side, this game is great for newcomers, as the easy and medium modes are much easier than GH games. The note patterns that you get in expert guitar mode are very easy, but the developers seemed to just be intent on negating this by giving you a crappy controller and making hammer-ons and pull-offs only work half the time. The game is playable, but not more than one time through if you're playing guitar. If you get this game, definitely either sing or play drums. Harmonix seems to invest a lot more time developing for drummers and singers, because playing the guitar in this game sucks.