First things first - everyone with a PS3 should buy this game. The graphics are unbelievable and the face recognition, motion capturing and voice acting are excellent! I personally really enjoyed solving the cases, especially the ones nearing the end where you take charge of Kelso.
Also - really good if you're a trophy collector too - lots of stuff to keep you occupied when you have completed the storyline. I don't think this game is a keeper though, once I have 100% the game I will be trading it in.
I would have really enjoyed some kind of multiplayer mode with the game, then maybe it would have got 5* from me.