IMHO it comes down to the financial position you are in and whether you have a family or not.
If you are single and have a small amount of savings you can buy a small place and take your chances on the real estate market here. No guarantees there as we all know. However at the moment still a good bet.
If you are with family then you need a bigger chunk of your own money to afford a big enough place. As numero crunch pointed out if you have kids (as I do) you pay alot out of your own pocket.
So if you are single SO Hong Kong. If you are a family DEFO where ever unless you got a large chunk of change to plunk down on a flat. Although you might just love Asia !! My family are really happy here, but will have to go home soon as the little one is getting pollution related breathing problems. Really too bad as Hong Kong has been great (albeit expensive) for us.
As for the DEFOs an how they will affect SOs. There is no way that it will be quicker now to upgrade as an SO 4 years will continue to be the norm.
I feel for my SO friends as it really is bad timing for them. Also to add insult to injury the company is offering DEFO slots to SOs but they have to quit and rejoin loosing their seniority in the process. That is just wrong !
FG