I think the Chevy vs Ford thing has taken over the discussion and we've overlooked a basic premise.
Potential buyers of any ATV brand should keep in mind these are converted snowmobile and/or motorcycle drive trains on a different (very lightweight) frame. They were envisioned from the get-go as play vehicles or as a way to get from point A to point B, but as their engine power and ability to travel over rough terrain was enhanced from year to year, people realized that with a little ingenuity they would make good small transport and carry-all vehicles (especially UTV's with small pickup beds) for working on farms and ranches, carrying tools, working fence lines, and even pulling a small trailer load of stuff. However, as we all seem to do with anything that hits the market, people started using and abusing them to do things they were never intended to do, even substituting them for SCUTs in ground engaging work such as mowing, plowing, disking, seeding, harrowing, and pulling heavily loaded trailers over rough ground. As most of us have, I've seen people doing totally insane things with an ATV, things that if not always dangerous are usually always stressing the machine way beyond its intended limits. An entire cottage industry has sprung up to sell all manner of "farming" implements for use on ATV's--if you own a small tractor, just check the ATV section of your Cabela's or Northern Tool catalog if you want a laugh. Then there's the group, usually from age 14-29, who think any ATV with less than 75 hp that won't do 70 MPH on a trail or gravel road is a wimpy machine or has a wuss driver.
The predictable result of taking practical application to extremes in many cases has been a lot of disappointment in how much ATV's can take in rough service--which isn't all that much, regardless of brand name. Broken axles, suspensions, transmissions, burned drive belts, etc. are common if they are intentionally mistreated, as would be the case for ANY machine that's regularly intentionally pushed beyond the limits of what it was designed and built to do.
There will always be some quality of construction and design differences between brands and models--or at least the brochures and magazine ads from the manufacturers will claim so. Usually, but not always, the differences are directly related to price level. The bottom line is as long as folks try to use ATV's like SCUTs, they will continue to break them, with the result that their brand names will be cursed by their owners on the internet. However, just about any of them will make a decent and reliable utilitarian vehicle IF they are safely operated and used for their intended purpose, and not to mow the south 40 or plow through 3' deep mud soup just for fun.
My two cents, these days worth about 1.4 cents, I guess.