I have 2 kids in local school (primary). I chose the one closest to my house. I think it is impossible, as a non-citizen, non-PR, non-"old boy" to get in to one of the so-called better local schools.
They have no problems except find study of chinese mother tongue difficult because they had no exposure to chinese before going to school. We could opt out but I felt that exposure and whatever they can pick up is better than nothing.
They have friends at school and come home happy. The system is different and class size is about 40 pupils per. However, if you don't gripe or get in a tiff about it, kids adapt and do fine. It may not be the same as home, but isn't that at least part of why we are here.
There are no other caucasians in their classes, but I have seen a few other caucasians at the school. Some schools have more than others. I have heard of a school named Swiss Cottage that supposedly more than a few expats send their kids to.