My children are in a Montessori school. There is no evidence that children from most 'alternative' teaching systems do better or worse than those in 'regular' schools. My children like the school and it's conveniently located, so we have no intention of changing; but it's not the teaching system that makes or breaks a student (well, the more loony systems like Steiner schools have documented worse outcomes than other systems, so it's not hard to make schooling 'worse'; making them 'better' than mainstream systems is quite hard - despite all the armchair opinions on this topic here every other day when this comes up).
There's a lot of research on this; I read a lot about it procrastinating in the university library when I was wrapping up my law degree, so that was 5 or 6 years ago. I don't remember details. Probably if you start on google scholar and make your way from there, you'll find a lot of studies.
I was going to write that, there's a few books on Sudbury schools too
It seems like adjustment to society has nothing to do with 15 years of school because none of it matters, and just keeping people curious and off the streets has the most utility.
Provides a positive feedback loop that seemed to have positive results in the real world as well