My younger sister went to JAGS, which was her choice, as it was the right school for her. She got accepted into SPGS (and others) but chose JAGS.
My twin sister and I were Paulinas at the time, and the expectation was my sister would follow us, but she didn't.
She saw SPGS as an 'acdemic hot house', and it is, so it's a school for girls who thrive on pressure. My sister wasn't one of those girls.
My sister's opinion of JAGS was, it offered academic excellence, but as you rightly said, as it isn't often talked about alongside schools like SPGS, she felt the pressure was lifted a bit. She thrived at JAGS and headed off to Cambridge to read medicine.
As someone previously said, you can't judge a whole school on how one show has portrayed a small group, that would be mad.
After all, I know some Old Paulinas who would horrify people, you get them in all schools.