Mrs P makes a good point - my DF got tossed out of private school because they couldn't keep up with him (yes, i was quite astounded to hear that) - at least in public school the systems may be a little less structured and she my have more opportunities to move forward.
I left the private school i was at (grade five) after a term, because they were holding me back, so i guess i'd say public education is just as good. But then again, it's sort of a trial-error situation too.