Only ever done J, terminating in China. they're good. Guangzhou Airport is a bit confusingly dysfunctional at times. in J, with tight connections you get a lot of help (carts, guides through the various checkpoints and gateways)
On flight service was fine. Modern fleet. competent crew. It's a different sensibility about appropriate behaviour in the air maybe for a lot of the pax, but nothing I haven't seen on other airlines.
Good thing about asian airlines? the pax getting off in Asia, from Asia universally sleep on the flight. Its quiet.