Generally, private schools. The public schools are poorly funded and resourced, and teacher salaries are so low that often the teacher has another job as well - meaning lack of time to prepare, rest, and think about the students. Sometimes the other job may interfere with the teacher's ability to turn up and teach the class.

And various other reasons - teacher qualification levels, for instance, or private schools being able to teach in a language other than Khmer, a more diverse student body, availability of international curriculum (in case portability/continuity is an issue), higher fees mean better resources can be afforded, etc...

BC