I recently had my first and last experience with AC.
Whilst I only speak from experience of two flights (LHR-YUL-LHR in March this year) I must say I was extremely dissapointed with Air Canada.
Customer service was terrible, FAs were rude, was amazed to find no PTV in economy on an A330 (oldest of which delivered in 1999, come on AC what's that all about?!).
The check in at YUL on the return was a shambles, 3 flights departing at once (CDG, FRA and LHR) all checking in at an exceptional four desks! Queued for about an hour (honestly!).
The check in assistant was rude and not apologetic of the fact my reserved seats (reserved with AC direct by telephone in both directions weeks before my departure) had been given to someone else.
The only good thing was flights were on time both ways. But that really was the only plus.
I will fly with BA next time, it is worth the extra money by far.
I used to love the smell of Jet-A in the morning...