I've done alot of riding in my day. I've seen them all: Polaris, Honda, Arctic Cat, Yamaha, Suzuki, except a Bombardier.
Go Honda and you won't be disappointed. My family has always owned Hondas. In my opinion Honda is the best ATV there is. Sure, you pay more, but it's worth it. I have a '96 Honda Fourtrax 300 2x4. I have done nothing to this bike but change the oil, oil filter, air filter, and changed spark plug twice. It has never had a single problem. And I'm no "grandaddy" rider. I push this bike to the limit and drive it back every time. It has seen hell and high water and has lived to tell the tale. Every bike except Honda has major problems in the water. I know, I know, they aren't made for the water; but there's always that "what if?". I have had mine up to the gas tank in a river and still kept driving across!
The only problem I have seen with Hondas is on the 97-00 (as far as I know) model Foreman 400's. The brakes don't last long. I have ridden 3 of them with zero brakes. Of course this could have something to do with the sand and mud these bikes have been put through, but mine has seen some pretty hairy stuff and still stops on a dime.
Honda is the way to go. Period.