There have been a few thread about that some time ago. Do a search.
But from what I can remember from them, the HKAC is ludicrously expensive, populated with rich HK business types who, for some strange reason, preferred that to a membership at the local flashy golf course, and all you can do are visual patterns in the cosmically vast airspace that is the new territories, in <2 miles vis, and only during the weekend...
General advice was to go to Thailand or the Philipines and find a good cheap club there.
And why do you want to get a HK PPL, unless you're going to work for a local operator, in which case they'd get your license converted for you anyway?