Westbound: AA. Because I will mostly be awake, so their WiFi is useful while their habit of leaving the lights on and FAA-imposed ineffective curtains are irrelevant. The seat is good and the IFE is better than most BA (except Super-J).

Eastbound: BA 744 UD or A380 UD. Because I will want to sleep, so the quieter BA staff and actual effective galley curtains combined with the comfortable seat for sleep will ensure better rest.