I had a dude at an msf course show me the difference. I took the course with a friend just to do it and keep him company and maybe learn something. I had always thought that you pull the clutch just before stalling, and told him this. He had me get up to 30 then emergency stop my way. Then he had me do it while clutching and downshifting and, damn, wouldn't you know the distance was probably 2/3 of what it took the other way?
Clutch. It works better. And do it every time you stop at a light or whatever so you start just doing it without thinking.