For sixth form I went to what's commonly regarded as one of the top public schools in the country
The educational standards there were fantastic. We were taught to debate and think laterally, only really picked up the A level syllabus in the spring term before the exams, the rest of the time the teachers taught round the subjects and we had an incredible breadth of knowledge as a result. Like most of the girls (and many of the boys too)
I went to Oxbridge, partied the first year and got a first in the end of year exams because the school had taught me it all already. I went on to have a fairly glittering career. I'm not sure if I'd been to any other kind of school I'd have had the confidence to pursue that type of work as it is notoriously competitive. Obviously, we'll never know what might have been but I am very grateful that my parents sacrificed a lot to send me there.
However, the pastoral side of the school left a lot to be desired. If you were in any way a misfit, you had a very hard time. The swimmers are now in top jobs and you see their faces all over the newspapers. The sinkers ended up in rehab, psychiatric units etc because either academically or socially they weren't up to the mark. It was especially brutal for the non-pretty girls - if my dds aren't gorgeous there's no way I'll expose them to that level of scrutiny and criticism at the age of 16. So
Before that I was at a girls' private school, also with a very good rep. With some notable exceptions, however, the teaching was fairly bog standard - esp in science and maths. The school relied on the fact it had a lot of clever, notivated girls to get its results. My dad says that he paid for me to be surrounded by such girls, so it was still worth it and he may have a point. We sparked off each other, had a lot of fun, were very creative writing songs/alternative magazines etc but by sixth form a lot of us were all restless and wanted to move on (and get a chance to snog more boys). I lost touch with everyone who stayed on in the sixth form but I get the impression from others that most went on to very safe traditional jobs - nothing wrong with that but I don't think they were pushed to be all they could be.
I used to think private education was the be and end all, but now am not so sure. Have loads of friends from comprehensives who have great jobs and lead happy lives AND don't have an obsession with where to send their dcs, like me which can only be healthy. I think when all's said and done it is largely down to family background, even at the fantastic school the kids whose parents were divorcing (and there were a lot) didn't do as well as those from stable homes. Sad but true.
Having said that they'd all have benefited hugely from the teaching at my public school. I think I was really lucky and I wish - though fail to see how - such teaching could be available to everyone.