Have you done the McGuire program? I just learned of it and sound better than anything I have found in decades of looking. The negative reviews I have found are based on people that do not stutter. I really like their explanation (for the Beyond Stuttering book) >Stuttering is failure to articulate and/or vocalize certain sounds of certain words. It is caused by fear, that turns to panic, that freezes the diaphragm, stopping the vacuum in the thorax from releasing; leading to air not flowing over the articulators and vocal cords, leading to struggle and distortion in those structures further lead to tricks and avoidance, resulting in the emotional habits of guilt, sense of isolation and low self-esteem. This all feeds back into the fear, causing more stuttering.