There have been a lot of threads on this. Do a search, if you are inclined.
Based on reading the book, my feeling is that the philosophy is pretty sound, but that the examples are terrible. Many of the examples are punishments that are dressed-up/manipulated to seem like "consequences." But are still really punative. I was frustrated with the book, because I kept switching between agreeing and disagreeing, with equal vehemence. I'd like to rewrite it with better examples!
I think my conclusion is this: Its not for me and mine, but I can see how it would be helpful in a family where there is abuse or chaos --- as a bridge to more thoughtful parenting practices.