That is a pretty solid list IMO..... but Leadbetter? Not in the same category in terms of breakthrough teaching IMO. I'd put Knudson on that list before Leadbetter......
I saw a 'swing setter' in action at the range today (LPGA) - no names, but lets just say she was really looking frustrated and swinging poorly. She picked it up and tried it several times, but with not so positive results.
Nick Dougherty, Faldo's protege and a recent winner on the European Tour, uses one and thinks it is effective.