Im not trying to Boast or offend anyone but ive probably had more quads than anyone on this fourm, 8 To be percise, Im a Mud rider and Go in water above handle Bars, Im a member of an Extremely popular Fourm on mudriding Called Highlifter, here are the Statistics: well ive owned 3 Hondas and The Rest Yamaha.
Honda Trx300/Fourtrax are the Best in honda range, Speciallize in Reliablity.
Yamaha 350/450/550/660/700 Grizzly best in Yamaha range speciallize in reliablity, Fuel economy and power, Also you can get a Yamaha rhino Car type thing with a Back end that can tip.
Polaris Sportsman 500/800/850XP, Extremely unreliable Bikes, they may last longer for People that never ride them, But they speciallize in Power.
Kawasaki Brute force 650/750, Burn belts faster than any other, Its a V-Twin Beast, One of best for pwoer
Can-am oulander 400/800, Power Is amazing
Suzuki King quad 750/700 There not the best bike but quite reliable but not the best of bikes.
For smallholdings The bike to Buy is A Yamaha Bruin 350/Yamaha Grizzly 350-700 or else a Honda trx300/Fourtrax.
EDIT: Sorry just realized how out-of-date this thread is.