I visited one Sudbury School and to be honest I really didn't like it. The school was way too chaotic for our son. It lucked structure and even though I think kids need some freedom this was too much for me. Our son would be lost there.
There were other things which bothered me. The space the school was using looked old and not well taken care off. I would go as far as saying that it was quite dirty and disorganized.
As with every program the philosophy may be good but it all depends on the particular school and teacher.