Ok without writing a book. Here is a link I found that should explain it.
http://www.teamnovak.com/tech_info/b...ensorless.html
The basic idea is that a sensored system allows for a smoother start. When I had that other ESC I posted earlier if I tryed to just be as easy as possible on the trigger to see how slow I could make the truck roll at first it would cog a little then go. But with my new mmp sensored ESC I can roll it slow enough to read the writing on the tires. very smooth.