Well if Brion says it's ok...
The overriding factor for me is that Canada is, in general, too cold. Same sticking point I would have with living in Vermont, however, which I think is probably a pretty excellent place to live.
(and I know the summers are beautiful...I'm talking about the winters)
When you start comparing with the world in general, both are pretty amazing countries in many ways. Europe is plenty awesome too I would say. Everyplace has its ups and downs I suppose.
Canada and the US are such similar places though that they are often compared. I dunno, Canada's politics seem to make slightly more sense. Culturally I think they're pretty similar, except perhaps that Canadians I have met seem to have, on average, less attitude than Americans and in general are easier to talk to. Less of an urgent need to prove that they are important and unique human beings I guess. Americans are always checking each other out socially, like "What's your cool and awesome thing? And why haven't you asked about mine yet?" Like each person needs a selling point or brand identity. Am I off-base here?
edit: what are the freedoms that other countries have that Americans don't have though? Oh right, gay marriage. Ugh yeah that should be such a no-brainer (legalizing it). But yeah in general America still has a lot of freedom, at least of thought and expression.