I've done both Qantas and Air Canada J in the past few weeks. Qantas was a bit of a rude shock having come off a BA flight in F: sloping seat, no privacy screens, no storage or flat surfaces to put anything. On the plus side, the food was good and they give you pyjamas. I think the plane was an A330 with seats in a 2-2-2 configuration - I chose one of the middle two so I didn't have access issues.

AC was a short 6-hour flight from YUL to LHR, necessitated by a short-notice cancellation of the BA flight. BA would have been a 767, so "old" NCW. I quite liked the AC seats: plenty of flat surfaces and when they are fully flat, I felt they were more enclosed and private than BA, with more shoulder room. But the joints between the seat pads were very noticeable and quite uncomfortable. And I found there was less privacy when the seats were upright than BA with the dividers up. There is also nowhere near enough overhead locker space and the food and wine were horrible.

Overall, I would say BA wins on privacy and ties with AC when it comes to the flat bed. QF wins on nothing when it comes to the seat and I didn't sleep at all well on the flight from SIN to ADL, although this could have been because of disruption from the "wacko" in front of me (not my word, but that of one of the FAs).