Driven both my Z800 and a RZR900 and to be honest, both ride the same, the 900 had a lil more pep but as far as fit and finish, my Z looks like a Cadillac in comparison.
Build.... I thought the Polaris would be better, until he said all the problems he had with it. So like anything else. Guess it's all luck of the draw, treatment, preventive maintenance, and care.