It depends on your age, how long you want to work and what you are looking for.
My opinion about these 3 choices:
KA for quick command and then work part time somewhere else.
CX for career if you're young enough to accept a long wait before command and you're sure you will be happy staying in HKG that long.
HKA would be a compromise between previous options with a bit less money than KA/CX.