So depends on what kind of riding and if you want to take people. With Sxs , trees and sidehiils sometimes have issues... nothing a chain saw won't fix ��, some times the length cause issues in tight trails... same can be said for the 2-ups. And finaly do you want to take people with you, if so sxs is better.
If u like response and challenge then an atv is what u want.
I have 2 atvs and one 2-up, and will only get a SxS when I get too old... solved the passenger problem by getting the wife one too.
If I still had young kids the I would also go SxS, so.. it is really what is your intended use.