Dealing with the original question....
....rather than other issues that muddy the waters.
There are actually some very valid and worthwhile comments if you sift through the replies to your original question.
You must initially decide how risk adverse you are. Buying a house has the potential to set you up very nicely but it ties you to Hong Kong should anything go wrong. How much of a risk you think it is to lose your job/liscense only you can decide, regargless of what some will rant about on this site.
As has been stated the smaller the initial outlay the easier it is to get equity in the property and bug out should anything go wrong. For me it was $5 mil (as was mentioned 3-5 mil is a fairly safe target but don't expect much size wise)
Obviously the greater the purchase price the bigger the potential gains but the greater the risk if property takes a dive or you have a 'bad life event'.
Renting removes all of this risk as you simply up stakes and leave. The figures by Numero and others nicely explain how much you will get for either option.
My advice, for what it is worth, is take your time. Get to HK, rent a place for at least 12 mths and get comfortable. Then start your research, whats the market doing, where do I want to live, how big place do I need for my family, do I feel comforrtable with work, do I actually want to live in HK for the next 5 years or so and lastly, what realistically can I afford given the large initial outlay and associated costs.
If you think you are going to be here for a while I would go for it. If you have time on your side it obviously reduces the risk as you can ride out the dips and sell in a boom. The Golden Rule is to never be in a position where you are forced to sell. We purchased after 1 year by borrowing the deposit against one of our overseas properties, the mortgage has been paid down by CX to 3.5 mil and the house next door just sold for 9mil so for us it has been a great investment.
Hope that helps