For now, I'm giving it 5 stars, and I'll continue to assess this as we fully implement it with our son. And I'll explain why.
I've now read the book, and did really enjoy it overall. No quibbles with it. But as with any book of this sort, where the rubber meets the road is the key. It's the application.
I've already seen some improvement with our 5 year old. He's terrible about interrupting adults as they/we talk. As an only child, I suspect this is worse than normal, and is worse than I've observed in most other children. Through implementing just one portion of this book, in a matter of 2 hours we have already begun to see transformation in his behavior. He recognizes that we know he wants to speak, but he is now (mostly) waiting his turn with his hand upon my hand (or my wife's hand) reminding us that he is there patiently waiting his turn to speak. We celebrate each time he does this (positive feedback cycle!) and he's thriving on the reinforcement. How this will work in the larger world remains to be seen, but it made a difference at the restaurant on Mother's Day, and that alone makes the book worth whatever it might cost.
Generally I'd shy away from this type of book, but having read up about it online and seen some first hand testimonials I decided to give it a go. As it continues to be rolled out I'll try to stop back and update this review to keep it current over the next few months. But so far, I'm really liking what we are seeing. It is written from a Christian parenting worldview which I greatly value. Give it a look and see if it might be of help to you!