Okay, granted, I'm ¼ Scottish (give or take), so I'm not fond of spending money for anything I can get for free, but I especially dislike sites which get the holders of public information (like census results) to sign exclusivity agreements, so that they can put that public information behind a paywall. As I put it to a friend of mine a while ago, "Why should these guys have the right to hold my family for ransom? Okay, okay, not my actual family, but their information." But I have a particular grudge against Ancestry in particular.
Maybe it's because I've been using the LAC site for so long, but I've learned all kinds of tricks (not just wildcard searches, but narrowing down, sometimes right to the census tract, search by age, and so on) to get LAC to cough up the results, even when there are typos. (And the LAC staff probably dread hearing from me about those typos.)
And, again, probably because I've been frustrated by Ancestry's search engine so many times that I don't even try using it anymore, but I can never get it to work. When Ancestry had an exclusive on the 1921 census results, I could not find my grandfather and his family, even though I knew, not only the city where they were living at the time, but right down to the street address. Once the 1921 census results were finally made available on the LAC site, I found them on the first try.
Plus, it annoys me when people think that putting "Ancestry.com" counts as a source. (I want to write back, "That's not a source. That's an advertisement. At least put in the link to the document you're looking at, for the benefit of other people who use Ancestry." but I don't. Even if I can't actually be a nice guy, I feel that it's important to maintain the illusion.)
So, if Ancestry works for you, then fine. But I will never be a fan.