This I was asking you.
I don't know nothing but the interface speed. Nothing more.
Yes, they are exaggeratedly high priced, from my point of view, and even I don't know if they are good at something.
My goal is to make something like those from the MIT, or if it is possible, even better. I know that their quadcopters (from the MIT) have ESC's running at 1Khz, and I believe that the only way of reaching their performances is to match their physical quadcopter's characteristics, thus I need this type of ESC's and motors.