I flew Etihad SYD – AUH last October in J. The food was excellent, the seat was really comfortable. The only (minor) grumble I had is that it isn’t a complete bed, that is, there is a section of the bed missing between seat and otoman when fully extended (a few inches if memory serves). It is a proper flat bed with plenty of width at the shoulders. I had a window seat and was impressed with the level of privacy it afforded. As the seats have a staggered layout at the aisles, you are not required to climb over anyone to get out, which can be a little annoying with BA whether you are the climber or the climbee. There was also pretty good storage as well.
The service was prompt and efficient, but a little robotic. There was a lack of banter and generall chirpiness that one seems to get with BA long haul.
Another slightly annoying factor is the sanitisation of the films and TV shown to remove any naughty words etc.
It’s a bloody long run from AUH – SYD and vice versa, so comfort is important and on this point, Etihad scores very well.