It's even better than Sing Star or Guitar Hero I tell you :) You get to try out your skills with the vocals, the drums, the guitar or the bass. So far, I've tried vocals and the bass, mainly 'cause others (who have more skills than me on the instruments!) have hogged the drums and the lead guitar.
Customizing the game is easy - new songs can be bought online, and if the X-box still have some memory left over (:P) you can create your own profile (musician) to rock on with. Mine looks a little like me - the short brown hair and perky attitude, but she dresses in pink (!), which I NEVER do. This 'cause "her" band name is Oink's Pink P! The band logo is a pink little pig with a space opera lady for a rider... Now that's some serious therapy for you!