AY offers a fine Asian service (this is their business plan, to grow Asian traffic) and as J is their top class it is very nice; better food and wine than F on many airlines, and better than CX (but only on these routes, not true of AY in general). The planes and seats are old, but comfortable for sitting -- not for sleeping; however the CX J seats are *awful* for sleeping, despite having great specs and ostensibly make into a flat bed at roughly 10 degrees inclination. In practice it doesn't work and you wind up using it as a seat instead of a bed (very comfortable as a seat, nicer than AY has, but AY J is better than AA F domestic seats, to put it into perspective). I love CX dearly and go far out of my way to fly them (since I rarely fly on their routes), but I would pick AY instead in your scenario.