i recommend german swiss coz it is good reputation and i have friend's son studying there. also, they have both german/swiss stream and english stream for the students
My daughter goes to GSIS and I do hear that it is one of the best. 2 streams as mentioned above. The only thing is they do start very early. We live in the mid-levels and my daughters pick up is at 6.45am !
GSIS has very stringent entrance requirements - no idea what they are but my daughter got in based on a 1hr of interactive intervies etc. It's supposed to be very academic but again don't hear my 5 year old complain about it.
French Intl School also has a very good reputation. Also has 2 streams.
HKIS is good if you want a bit of an American kind of education system.
Christian Alliance P.C. Lau Memorial International School - CAIS
Think International School
Sear Rogers International School
Norwegian International School.