New or used I'd be looking for a Yamaha 700 Grizzly.
(assuming you meant 4-wheeler)
Some guys like Honda.
We move cows in some fairly rough country with ATV/UTV's and the Grizzly is a very good machine.
If speaking hard use and a UTV I'd get a Honda. We have a 900 Ranger and it's been fine but I don't bomb around too hard in that machine.
i have one of those, p.s., independent suspension, disc brakes, very comfortable to ride. has a low/high, 4x4, also a locker to make it true 4x4 on all tires. will do about 70mph on the flats. rarely use the low range, not needed most of time. it has the ability to scare you in where it will go. also has a good trailer towing capacity.
