Worth the purchase after it's been out long enough for a price drop.
Even with some minor framerate issues during races, the graphical presentation is as good as any other 360 racer I've played but still seems like it could've been polished just a bit more. There is a very nice replay mode after each race that gives some great angles of the action. Players can skip the replay if they choose to, but I'd suggest checking out a race replay if you have HDTV.
The controls on MotoGP will definitely challenge you. True human physics, weight shifting, braking and timed acceleration are all must-learn skills if you hope to compete. The game has quite a few built in aids like direction arrows and an overhead view of the track to help you anticipate corners better. Again, the player can choose to ride without help , and it's always nice to have that option as a gamer, I suppose. Invest some effort into learning the controls and this game can become an addiction, despite some very minor shortcomings mentioned earlier.
With lots of bikes to purchase, parts for each, tracks to unlock, riders to unlock, and a quality online experience, MotoGP is deep enough to warrant a purchase, even if you can hold off long enough for the sticker tag to drop a bit. It will. Solid weekend rental at the very least. Check this one out.