Id have to agree with the 4x4 option but, that depends on where you plan to ride. Where I ride is all overgrown with mud pits and creeks so my polaris does great. Now dont get me wrong here, a bunch of my buddys ride sport quads and get through things pretty well but, tend to have trouble in the deeper parts of the creek and mud pits and end up needing pulled out occasionally or having to make many attempts to get through a rough spot. I have rode both types but, I prefer my big 4x4 especially when riding for 5-8 hours at a time. If youve got a big open area to really get some speed then sport bike all the way but, for aggressive trails Id stick with a 4x4. Plus they are starting to make the new utility bikes with much sportier handling than the older ones.