I like Air Canada for the most part. Their business class flights to London are good. Their economy flights around Canada are good. I tend not to fly them to the US as at least one of those legs ends up on Air Canada Rouge or United, neither of which I like.
I find the flight attendants on AC friendly and the seats to be fairly comfortable (I have long legs).
I'm not thrilled that they divested Aeroplan and are planning to replace it with a new program in 2020 (points won't transfer over to the new program). Loyalty programs seem designed to punish their customers these days.