sensored, u need to connect a sensor cable from your esc to motor. it helps the esc to know the position of the rotor for control..

speed control, it adjust the amperes to the motor. more current higher rev.. braking & reverse are part of the task of esc... for the pro spec esc they do not have reverse function..except forward throttle & brakes.

most esc does the same function, some u need use sharp object to poke like the lrp esc for setup & program.. while other they give u option of program card which rather interactive. the choice of esc depends on each individual requirements, availability & support.