Which is the best Dune Quad?

Yamaha Banshee is no doubt the best quad for the dunes. A close second would be the Yamaha Raptor 660 or 700. The Raptor is a 4 stroke and will be better if you plan on doing trail riding as well. But if it is mostly dunes than nothing compares to the screaming 350 twin two stroke of the Banshee.