I know a guy who is personally working with Bill and he says it's helping him. That said, even though his methods do acknowledge the importance of a system of influence for stuttering, the method itself is still focused on controlling/modifying how you approach the vowels and change them to make them easier. This may work for some and some people do just want to learn techniques. But for others trying to modify or work around their disfluencies is just resisting the unchangeable fact that you do stutter and that it's ok. The goal as I see it is to stutter well, not to control your speech.