I spent a fair amount of $$$ in this place when I was an exchange student in HK a few years back. Dont remember the specific amounts or how often I went or for how long a period of time.
They used three techniques on me, one was a manual "push tummy" massage, that hurt a bit and was supposedly meant to physically break down the fat tissue structures. Then there was a heat treatment to make me sweat, and while it was not a sauna, it should have the same effect. Then there were the electric machines that applied shocks to your belly, supposedly to stimulate the muscles.
They also gave me dietary guidelines (nothing fancy, just basic common sense), and it might have had to do with the money and time I was already spending that made me really watch my diet.
The results were mixed, I would say. Optically not as impressive, no six-pack, probably should have worked out more and not just reduce the fat. I do remember that I must have lost weight quite impressively because my pants became fairly loose during that time. When I returned to the US I could hardly believe the low weight that I had reached, to the point that I thought the scales were broken or I had not measured correctly or one pound in HK is different from the US.
So I don't consider it a complete failure, and not a resounding success either, but maybe not bad for some weeks/few months going there maybe two or three times a week. I still like the idea that if I am ever in HK again with time and money on my hand I'd try it once more...