Check out
http://www.worldsexguide.org/
I have been to Hong Kong a couple of times.
It is okay and rather expensive.
It was an okay stopover for a couple of days, but I would not travel half way around the world to go to Hong Kong.
I would not even want to stopover there again.
There are several flights per day to Bangkok. It is a short flight and inexpensive. I would highly recommend you go there if possible.
Never been to Japan. Everything is very expensive, although if money is not an issue, it seems like Japan can be alot of fun.
For what a couple of days of fun in Japan would cost, you could probably pay for a week of pleasure in Thailand.
