The general consensus on the AS Champion is that those sold by the big box stores tend not to be as consistent as those sold through the plumbing stores. As a result, while a good design, a significantly large sample of them sold to DIY'ers tend to be defective in some (often minor) way. Sometimes, the defects are not so minor. To a professional, having to exchange one along with the customer approval situation can be a losing proposition, and businesses aren't likely to survive long losing money. A homeowner, may not notice the defect (if it exists), but if he does, it is an inconvenience rather than a job or referral loss. So, if you get a 'good' one, you're golden, but too many people come here to also report that they don't work right out of the box. Some of the designs have some weird internals, and some don't. Therefore, sometimes, when it comes time to replace the fill valve or the flapper (or whatever is in your toilet), it's either harder to find, or costs more. Consistent, reliable products, like a quality tool, are things some people seek, and once you've used one, you tend to notice those that are inferior more and appreciate the good ones.
So, for about the same money, you can get something with a good track record, easy to find repair parts, or you can take your chances with AS stuff at a big box store. You might be more satisfied getting it at a plumbing supply house, but then, you may get lucky.
IOW, their stuff can work fine, but individual examples with defects turn up too often compared to others. Pot luck.
