Flew Air Canada for all legs of my North American trip in August: Brisbane - Vancouver, Vancouver - Portland, Portland - Calgary, Calgary - Vancouver and Vancouver - Brisbane (yes, that's a lot of money on flights!!).
They were all fine; the flights were all uneventful, and the service ranged from professional to excellent. The flight attendants were all at least bilingual, more than happy to chat and provide recommendations about places to eat (very important!) and visit, and I even met one who used to live in Brisbane, so we could chat Australian politics!
The long-haul planes were modern and sleek, while the flights to and from Portland were on turbo-props--something that I hadn't been on since flying from Thailand to Vietnam all those years ago!
The only complaint was the meals--airplane food is supposed to be bad (you know, pressurised air does things to your taste buds), but this, this was really ... not great. While not inedible, certainly if I had to fly Air Canada again I'd seriously contemplate bringing my own. If I'm allowed to be facetious, why does a Canadian airline not have Ceaser mix, or actual maple syrup?
On the whole though, it's certainly not a bad airline, and I would absolutely fly them again.