My DS2 is starting in YR at a small private school in September, it has 16 boys and 16 girls per class, boys and girls are taught separately for core subjects.
It is a non-selective school if your child joins before 9 yrs I think so there is none of this kicking them out before secondary if they are not predicted A's!! It also has a dyslexia department which is very highly regarded. The exam results are 100% A-C but they are not as academic as the grammar schools.
I like the fact that it is more formal than state primaries and the expected level of behaviour is higher than that in my DS1's state infant (we are still waiting for a place for him - there was a high intake that year so he will join in Yr 3 if not before).
There is nothing wrong with the state infant school but there is the usual level of classroom disruption and as it is becoming more and more popular, numbers are growing and it is no longer the small village school it was when we joined!
I also wanted the boys in there from as early as possible as the learn languages and other subjects they do not do in state schools so I don't want them to be behind at say age 11. They will get to know their class mates and there will be no disruptive moves later down the line.
I like the fact there is the old fashioned competition at the school - ie house points etc, they do PE every day, have music lessons from a young age (not offered at our local state schools) and generally more opportunities.
It will cost around £140,000 to send both my children till they are 16 but I consider it worth it for peace of mind that they will hopefully achieve their full potential (our local secondary schools are pretty grim so it can't be worse!!!)
I am just hoping it turns out to be everything we want it to be, we are not snobs or rich, we both have reasonably good jobs and have come into a bit of money recently so have a bit of back up. We just felt we should give our DC's the best education we can.