If only ski doo and yamaha, the ski doo would whoop the yamaha all dya long. It has a better ride with the rev based suspension whixh I believe is no called the SC-4. For speed, the Doo comes with 155 horse comapred to the yami's 138. The yamaha is heavier and you cant throw it around in powder. The yamaha is probably a litlle bit more reliable, but not much. But if you really want somethnig, get an older leftover F7. They are low in price, fast and are superior in deep powder, Boondocking . Plus they top out at a realsitic 105, and can beat a MACH Z in the 1/4 mile!