My daughter was the very bright all-rounder at her primary state school. It's an Outstanding school and she was identiied as Gifted and Talented at Reception level, so extended very capably within the state school. we were very happy.
Then she won a 100% scholarship to a (good!) private school (which I put her in for on a total off-chance after a friend suggested it). She's been at the pricate achool for a year now. The differences are extreme.
At the state school she was one of 25 in a class - small for state really, but it meant the teachers had less time with the kids. my teacher froneds say that once you get to the 17th name in the register you feel like there's a billion of them in the class. She now has a class of 12. She does an hour of proper sport every day with a PE teacher - not half an hour chucking bean bags into a ring leek she did at state. She has 2 hours of music with a proper music teacher each week. She learns instruments. She does sports clubs, art clubs, drama clubs, choir, band, all included in the curriculum, all with dedicated teachers. She has breakfast and after school clubs included in the cost (so free for us) with homework supervised by teachers. Her teacher really knew her, and was available at any time if we had problems. we could email her directly about the smallest thing, and she'd be able to answer quickly, and knowledgeably.
The difference is staggering. And it shows in her: she was always happy to be at school, but now she's excited, engaged and bubbling over with enthusiasm for everything - even though she's no longer effortlessly top of the class (she's not the only scholarship girl!)
my son will start at the state primary this September. It breaks my heart that we can't give him the same advantage that his sister has at her school. But he's not the scholarship type, and we can't afford it as I'm a f/t student.
Outstanding state schools are all very well. BUT to get the "Outstanding" grading, they lose out on a lot of the things that make the private schools worth it.
Wokring on my experience of private and state, if I could afford it, I'd send both of mine to private school,in a heartbeat.