They went with the 500 cc engine to keep the weight down and hp down to appeal to another sector of the snowmobile market (i.e. the Doo Freestyle and other small sled). Quite frankly, I like the concept. I will not knock the performance unless I am disappointed after riding one, but I doubt that will be the case.
At any rate, Yamaha clearly is heading in the right directiion. I have lost count of the number of guys (Poo, Doo and Cat riders) who rave about the Apex and Attak. This entry level sled will only contribute to that.