Frame is notorious for breaking especially at the cross supports - definitely want a gusset kit. Frame is only like 0.065" wall thickness too. Radiator fan comes loose and crashes into the radiator which usually ends up with a hole in your radiator and a tow back to camp. Most guys strongly recommend the extended factory warranty and dump them when the warranty runs out. They complain of several small issues, but enough to put them in the shop quite often.
RZR stock width is 50" - the only SxS legal in MI on ATV trails. The RZR-S comes with factory long travel and is 54" - not legal for ATV trails in Michigan. Rhino and Teryx are both around 54" in width. The new CanAm's are supposed to be pretty nice and alot faster than a RZR. Rhino/Teryx can be converted to four seaters whereas the RZR cannot. I ended up with a Rhino because I wanted a 4 seater so the whole family could ride.
Google "TR-54" form is you want to make it street legal. Michigan is one of the most stringent states around for making them street legal - you'll need automotive style windshield ($500), DOT approved tires and rims ($1000), functioning wipers and reservoir for fluid, license plate bracket and light, headlights, tail lights, turn signals, brake lights, horn, rear view mirrors, and a few more items that should already be on most SxS's. When I added everything up, it was around $2500 to make it street legal in Michigan. Other states like Utah, Arizona, and Illinois only require the $200 "street legal kits" you see on ebay which are just horn, blinker and lights.