I believe that outside of a few really atrocious school systems that have lots of crime or other distractions, it's not the school that matters as much as the students. If the student is willing to learn and put in the work to get good grades they will. If they're not then it doesn't matter how good the school or the teachers are. Some schools may be better suited to help kids individually but that's something the parents could provide with tutoring. I think most people choose private schools for religious reasons or for social acceptance. Personally I think kids educated in public schools experience much more diversity and are much better able to deal with the real world.