It's Air Canada, eh?
I don't fly AC all that often (a few times per year) but I've had good luck with on time arrivals and departures, even into O'Hare. Flight crews are generally ok & the fleet seems well maintained. No airline is perfect, but keep in mind that I fly the worst of the worst on a regular basis (American + Frontier, I'm talking about you!) so AC is decent in my book.
Big shout out to the gate agents at Toronto-Pearson, though. I changed my flight in the kiosk which then decided not to give me a boarding pass. The line for "check in assistance" was approximately 10,000,000 people long so I straight up begged for help from a nearby staffer. They were able to get me my pass fast and I made my flight as a result, getting me home several hours earlier than planned.
Thanks AC!