I'm personally fond of their Korea/Japan service... HKG, not so much, but better than Spring/Juneyao, I suppose.

aulrik possibly hit the nail on the head re summary of MU; fine as long as things don't go wrong. But, when contingencies arise, be prepared for some serious airport time (hopefully in the terminal).

skimsogood: 90 mins is doable, but a little on the tight side because you will probably need to border control, exit the airport, check-in, and then clear border control again. While that may sound insane, this is indeed how MU to MU transfered as of last month... this is the type process that could be changed (for the better) at any point in time, but just warning you. I would advise you to do a true stopover and spend a night or two in SH (December usually isn't super cold).