Both will overheat. have to keep rads clean no matter what you ride, I would say go for the sportsman the 4x4 system is better then the king guad. Both are good machines, personally i say test ride both and see witch one suits you more.
King quad all the way,4x4 on polaris is a pos,wiring on polaris is a pos they are agricultural compared to king.But buy polaris if you like wrenching lots
How is the polaris 4x4 a pos never had a issue. you put it 4x4 and you get 4x4 no diff lock worry about just works. Wait guys i have to stop and put in diff lock or oh chit i forgot to put it in diff lock now i am stuck, none of that with the sportsman, and i have 3 sportsmans on has over 5500km on it never seen more than maintnece till my bro rolled it down a hill and we had to rebuild half the quad. Personally i dont care what you buy there both good machines as long as you have fun thats all that matters.
I would say go for the sportsman the 4x4 system is better then the king guad.