I think that primary school is more important than high school. If children are equipped with the right tools when they start school them can excel in any high school.
This was my experience. I went to a small private primary school and then on to a large public high school. (My year level at high school was larger than my entire primary school). I believe that the education and love of learning I was able to develop early helped me get through high school. I was painfully shy as a child and would have gotten lost in the system as I was too quiet to be noticed.

DH on the other hand was public all the way (his mum is a public primary teacher) and he agrees that he wants to send our kids to private school, at least for primary years. He regrets the way he acted up in high school because he was treated as a trouble maker when he was just bored.

We were also both raised Christian but don't go to church currently and aren't sure yet as to how we want to raise our children. I like the idea of them getting some religious education at school also.