The group that I hunt with has used Yamaha, Honda, Suzuki, Polaris and Bombardier 4X4's. The ones with the 400 - 500cc engines have all been gas pigs, making it impossible to take extended trips without additional fuel.
For pulling moose out of the thick stuff I (Personal Choice) prefer the Suzuki 250's with the high and low range. The bikes are light enough to push around trees and logs while the moose is hooked up. The Suzuki also has good fuel economy. The down side of Suzuki is the parts seem to be more expensive than the other makes.
We had a 500 Polaris burn it's belt off while pulling out a good size bull and we didn't have a spare belt with us. That was not a good experience.
One more thing about the Polaris and the Bombardier models with the belts. They are noisier than bikes with gear type transmissions.

Mike D.