Should Huntsville, Parry Sound, Kearny, mean something to me? (Serious question.)
I've owned every atv Yamaha has brought to the table, have a pair of Honda's in my shop right now, along with a Yamaha 450, and a Can Am 1000, (not to mention one or two behind the shop) and the one thing I can say for absolute certain, that in tough ground, nothing beats a lot of weight with independant suspension and a lot of horsepower under your thumb. It's always better to have power and torque available and not need it, than it is to need it and not have it. That's one thing the big machines do have going for them, lots of weight will keep your tires planted on the ground. Tires on the ground mean traction.
Sure it can be tough to sneak around the trees with a big atv, but if you are prepared for that, it isn't an issue. I've yet to find a trail I can't get through with the big bike, but I've certainly found trails that the smaller machines have a tough time with.
That said, big machines aren't the answer for everyone.