We had a return flight from Shanghai to Vancouver. Overall, the flights were standard - exactly what you would expect from an airline nowadays.
Some of the cabin crew on the flight to Vancouver were quite rude and curt at times; however, the crew on the flight back to Shanghai were excellent and incredibly friendly. It highlighted the importance of the 'service' you receive as a flyer, as to how your experience can change.
The food on both flights was terrible.
The selection of movies etc. was good and the seats were pretty comfortable.
I would fly with Air Canada again, for price and convenience, but there wasn't anything special enough for me to seek them out in future.