As an Ex BA gold, I would definitely say go for Etihad. The planes are newer, the inflight entertainment is better and the food's better too. The problem with BA flights to the Middle East (AUH in particularly) is that they use ratty old aircraft with tiny TV screens and rickety seats. The only argument in favour of BA is Dogmatick's above that you will end up with one very long flight and a short hop, rather than two medium-long flights.