I've only flown AF TATL J on the A380. I found the lie flat seats much more comfortable than DL's lie flat seats such as the A330, but not as comfortable as the flat beds on the 764. The A380 also had small bins to store items along the window which was nice. Food seems better on DL. Amenity kit from AF is nicer. Service seemed better on DL, more personal... but perhaps that was due to the nature of flying on the world's biggest passenger airliner with 62 J seats. AF lounges are nicer.