Happy to. Ultimately I have two very different DDs. And I think this is the key thing to keep in mind - there are no 'better' or 'worse' schools - it really is horses for courses depending on your DDs personality.
I'll start with DD1 - who is very academically able, and very focussed on that (too much, possibly, and I'm encouraging her to engage in more co-curricular stuff this year). Had decided she wanted to be a human rights lawyer in yr6 for example. Also sporty.
Knew she was bright, but figured we all think that, and also found it hard to gauge how bright. So went for a bunch of options: KGS, PHS, WHS, Surbiton, Sutton and St John's. She got places at all except Surbiton, (more on that later) and a couple of scholarship offers.
We chose KGS because we all, including DD1, loved the energy of the place. It felt very dynamic and forward-looking but also quite down to earth. It was clear she would be academically stretched there too, which is what she needed and wanted.
Our experience has been really good. They are pragmatic and attentive, have high expectations of the kids, both academically and wrt to self-sufficiency. It's not the most nurturing or pastoral place, but DD1 didn't especially need that. It's very close to home too - and that's a more important factor than many give credit to in this process.
In fact, I'd ensure that location is near the top of your selection criteria - a short commute makes weekly school life so much easier and more pleasant for the kids.
She starts rowing this year, and their boathouse and facilities are amazing. The only downside is the small campus can sometimes feel a bit cramped, and they have to commute to games at Ditton Field - but the kids don't seem to mind, and ultimately this has not been a thing. Ditton Field is brilliant when you get there.
The ones we didn't choose and why (briefly):
PHS - should have been the natural choice, both for location and the fact that I'm a GDST alum. Ultimately found it a little, well anaemic. It all felt a little formulaic and I just didn't get that sense of dynamism that I got from KGS.
WHS - fell too much of the side of an academic hot-house for me. Lots of talk about being broad and the arts and whatnot, but visiting and the whole process made it very clear that it's not really their thing. The art rooms were the most dismal and uninspiring that I saw at any school, for example. I was sad because I had a bit of a crush on the headmistress and very much wanted to like it, but ultimately just didn't.
Sutton - I really love this school. I wish it was closer to us, and that was the biggest factor is us deciding to go elsewhere. They're seen, unjustifiably as a bit lesser than their GDST sister schools, and for that reason I think they try a lot harder at everything. They suffer mostly from their location I think. But on heart alone, this school was my favourite actually. I love their attitude, their approach and they handle the admission process the best out of all of them. Handily their exams happen two months or so before all the other schools - and it's really friendly and kind, and that actually helps the girls not feel so scared of the process going forward. But it's a very pastoral, very balanced school, who work REALLY hard because they don't have the luxury of complacency.
St John's. Facilities are stellar. Location is a b*tch. They offer flexi-boarding which DD was very taken by and might mitigate the commute a bit. DD2s best friend has an older sister who transferred out of KGS to St John's for sixth form and is loving it, her younger sister (DD2s friend) has just started. Fees hike a LOT in yr9. More old-fashioned than a lot in feel, but by all accounts very pastoral and social - which is what it takes from its history as a boarding school. Ultimately the additional costs and location weren't sufficiently mitigated by the facilities.
Also, they were the least friendly to deal with by some margin - which put me off. DD got offered to come in for a scholarship interview - which she duly did, with all the prep that was required. (They had to prepare and bring in stuff.) She had a horrible experience and then ultimately we never heard another thing about it - we assumed she wasn't offered the scholarship, as we were just offered a standard place, but they never bothered to let her know - which was poor form IMO and left a bit of a bad taste.