recently experienced three legs with AC, all in Y:

DEN - YYZ: indifferent staff, no food on offer other than a few cold sandwiches and snacks for a 3 hour flight, but flight on time

YYZ - FRA: indifferent staff, mediocre food and to top it off breakfast came in the form of one slice of banana bread! On a 7.5 hour flight that's a first for me. At least were on schedule.

YYZ - DEN: indifferent staff, 75 minute delay sitting on tarmac for no-shows and offloading of their bags and subsequent congestion behind the aircraft, followed by 1.5h of no service (not even water) and finally being offered chips or chocolate for purchase as all other food offerings were either not stocked or already sold to passengers in front! Unbelievable.

This for the most expensive ticket to Europe I have ever paid for! I have flown AC previously, but this was certainly a low. On the return, I used Austrian and was very pleased with their offering. DEN really needs a lot more competition for international flights! A major advanatage of going through Canada remains being able to clear customs early while in transit and arriving as if on a domestic flight.