Richard,
T&C I think EK is the best (Bonus,pension fund..).
Although not a big fan of the " bling bling" culture of Dubai, everybody will admit that Dubai is much more organized,developed and efficient in what they do compared to Doha.
I would put Abu Dhabi (and EY) somewhere in between.
EY has a lot of ex QR pilots.( now if they are more happy there, I don't known)
So far I haven't seen any EY pilots flying with us(QR).