Do you teach primary students?
If so: Is a private primary school much better than a small good state school with with well behaved kids? Are primary children in large classes at a disadvantage to students in small classes, even where strong and positive parental support is available at home?
I teach in senior school at the moment, although have been Director of Studies in an all-through school and have been a specialist Teacher at two traditional prep schools.
I think an independent school is better than a primary school because of the diversity of opportunities for specialist teaching (eg science, DT, music), and onsite extra-curriculars.
However, I would say that if money is tight, save it for senior school.