If your kids loved HSM, they'll love this, too. There's absolutely nothing objectionable here, except the shameless commercialism of Disney (and who's surprised by that anymore?). Camp Rock toothbrushes and ipod cases anyone?
The main character, played by Demi Lovato, is ashamed of being the "poor kid" so lies to be part of the popular crowd. The Joe Jonas character, Shane Gray, sheds his superior "I'm a cool pop star" attitude after working at his uncle's performing arts camp all summer. Of course the two are attracted to each other. Of course there is the required snobby blonde girl (and her loyal followers) who must remain queen bee at all costs, and who, of course, gets her comeuppance in the end. Everyone's focused on performing in the "Final Jam" and winning a chance to record with Shane Gray (Joe Jonas). Neatly and predictably, they all learn their lessons in the end.
We got this On Demand before the premiere and my kids (daughter 10 and son 5) have already watched it three times. They both love it. I find it no more annoying than High School Musical -- perhaps the music is not quite as catchy as HSM.
When they're done watching send them outside to put on their own "Final Jam" among the trees.