I can't believe a used 420 Rancher was basically the same price as a brand new Grizzly 550. I would buy the Grizzly just because it was brand new, all things being equal. But they're not equal. The Grizzly has considerably more power. They're not really even in the same class. The Honda Rubicon is closer to the Grizzly 550 in power but it still falls short and costs more than the Grizzly. As Moose said, the Grizzly has 4x4 with diff-lock and the Rancher does not. You may not need it that often but it will keep you from getting stuck in the really tough stuff. The Grizzly has superior ride and I believe the Yamaha Ultramatic cvt auto is the best in the industry. Its a slam-dunk for the Grizzly for me.