I've no experience of having kids at any of them, but I did go to some open evenings last October. Visited Ribston, Crypt and DRHS. We spent at least 2 hours at each, but only spoke to the teachers and students, didn't bother with heads talks, we thought we would listen this year
We liked all the schools, all the kids were lively, intelligent and a credit to the schools. Main high-/low-lights for us were...
Ribston: really seemed to care about the whole child, seemed very supportive. Lots of outdoor space, a pool and dance studio. From my perspective no downsides. DD liked it, but preferred DRHS.
DRHS: very good results and seemed to challenge the girls to work hard. I'm not so confident in their ability/desire to support those who are struggling, but I didn't get a bad feeling if that makes sense, just thought Ribston seemed better in that regard. Not a lot of outside space on site, so I'm not sure where the girls go during break times. I think DD is drawn by the proximity to our house and the building...she quite fancies becoming an architect!
Crypt: liked the fact that it's a mixed school. Also felt supportive. Loads of outside space and facilities seemed to be very good. Again, from my perspective no real downsides. DD isn't so keen on a mixed school, but I prefer mixed. DD didn't get the feeling they are set up so well for girls, but I think that will improve year on year.
As I say, these are just our thoughts with no real experience or knowledge, just what we came away with.