I think the most important thing to look at when comparing J class offerings between the airlines is the price. Compared to CX, AY's prices are significantly lower. The food and wine are somewhat comparable (depends who you ask). IFE is a no brainer and seat comfort is nowhere near as good on AY.
All in all, AY for the price is very good IMO and I would have no hesitation flying them again. And considering that the M11 is soon to be phased out, the quality of service hopefully should improve with the roll out of the new aircraft.