Not that far in yet, oldest only 11, but so far not regretted the swap from state to private.
I do not necessarily think private is always better. But I am not really motivated by school GCSE results and just grades.
Yes, I would like my DC to get good grades. But more important, f I am honest, is for him to enjoy school, to develop of love of learning and to learn that you can achieve something if you put your mind to it.
For me, the big difference between State and Private ( in our particular situation) was that the state school believes heavily in " natural ability" and sets children accordingly. My DC was bottom set, which was perhaps fair enough. What the private school does is ignoring most of the " inate ability" and not do sets, but instead expect ALL children to do well, to raise the bar, rather than it all becoming a predestined thing ( bad Sats at 6 means low attaining for life, when really some kids just blossom later).
The higher expectations of children with a lower ability is worth a lot, IMO.
If your child is naturally academic, hardworking and does not care much about school sports, I would not bother with private school. In that case it might be even better to have come from a state school when applying to Uni ( as the tides are turning and society is becoming more anti- private)