I haven't travelled on AC for at least 10 years, and that is because my previous experiences had been so bad, on both transatlantic and domestics. A great pity and certainly not me seeing the worst as I like Canada and the Canadians, but the airline's service, specially on the ground, left a lot to be desired. I think AC had an identity crisis at least on domestic/regional routes and was never sure whether to be a legacy carrier or a LoCo. A sure way to lose customers at both ends of the spectrum.
My last trips to Canada have been on LOT, Swiss, AirTransat, Lufthansa, and KLM, all significantly better than my recalled experiences of AC.