Having done quite a bit of J this year on both BA and AC (mostly LHR-YYZ) I have to say that I now prefer to fly Air Canada given the choice of direct flights.

Things that make it better:
-Good direct isle access modern seat with good storage & feel of lateral space
-great size IFE screen - must be 19/20/21"
-Much better food in terms of quality and presentation. I have always wanted to have seconds of the main. Their signature dishes are particularly nice!
-Nicer J lounge in LHR with better food selection and much quieter than GC

Minor cons:
-better champagne and wine selection on BA
-for a flagship lounge in YYZ the AC lounge is just awful both in terms of ambience and F&B. Ambience and preflight dining in BA YYZ lounge is much better. Also LHR GC is miles ahead of Air Canada's YYZ lounge for a main hub lounge. AC wins on LHR-YYZ but BA wins on YYZ-LHR.
-I always sleep better on a CW seat. I think this seat is too firm for me and the fixed tray table/screen can get in the way when trying to turn in your sleep! Plus AC make an absolute racket on the red-eyes while preparing the cabin limiting time to sleep on a short TATL. BA wins on sleep quality.

I've also done PE on AC a few times and think that AC are miles ahead given the gradual erosion of the WTP soft product. 2 hot meals on YYZ sectors (I hate that dreaded basket pass on BA!), better pillow, same or very similar seat = AC wins.

Your thoughts?