Swamp,
My kids have been to ESF schools for nearly all their school time and they have had a fantastic education. ESF is in turmoil at present because of CEO election problems and teachers working to rule due to salary cuts. I think these things will work out soon one way or another. Do a search for ESF Hong kong and you should find their site. They presently run about 6 secondary schools and 9 primary schools. They run (obviously) an English curriculum which is at present under review to change to International Baccalaureate instead of A and AS levels. My eldest has just sat the IB and has not had any difficulties whatsoever with Uni applications...in fact they seem to respect the qualification for it's breadth and depth.
Like all things in life you only get what you pay for and I suspect that fees at the ESF are going to go up. I do know that German Swiss fees are much higher presently than ESF (for example) but possibly the differential will get less soon.
There is also the Australian International School in Kowloon Tong which had a good reputation but I have not heard much talk of it recently now it has moved into larger newer premises.