I've done long rides in the bush as well and didn't have to bring spare fuel. Oh, it uses more gas than a 400, but it's not all that bad. I've driven Yammys, Hondas and Can Ams as well. Maybe mine doesn't get ridden as often as yours does due to where I live, but it's no garage queen, it's just well looked after. Then again from the sounds of things yours must be a lot closer to being worn out than mine and probably beat up to boot. I had an interesting discussion with an ATV dealer a few years ago at the Dirt Bike, ATV and Snowmobile Show who handled both Yamaha and Suzuki. I was told on the side very quietly, that Suzuki vs Yamaha in was a case of pick'em because of how similar they are and that both are very good machines. I guess you know better than a dealer that sells both.
As far as bush rides, yah, I've been on them north of Sault Ste. Marie in March on the trails with tires on them. The other ATVs were 700King Quad, 700 grizzly, 350 Big Bear, 500 Sportsman and a 650 Brute Force - 40 miles down snowmobile trails surrounded by 3ft.of snow and across 3 lakes. No mechanical problems with any of the machines, but the Polaris did seem to get stuck more than the others and was harder to get out.
You say you use in all 4 seasons, how does your ATV make out in the deep snow? Do you have tracks or is your machine not powerful enough to use them? I can go anyplace a snowmobile can and places they can't!
To the OP,
From my experience, I haven't seen much go wrong with the newer Polaris, but they are all wheel drive vs. 4 wheel drive. When I bought my machine, only Yamaha and Suzuki had diff lock on the front differential - you don't use it all of the time, but it comes in handy in the mud or snow with tires on. Also, mine has shift on the fly 4x4, much of the time you can drive it in 2wd and conserve fuel and reserve 4x4 for when you really need it. The only other issues I've seen are with the Hondas and the electronic gear shifts. I know an number of people who have them on Hondas ranging in age from 2000 - 2008 and they've all had problems with the electronic gear shifts at one time or another. Many of the manufacturers have gone to cvt transmissions.
Roe+