Is there a halachic difference of which electric shaver I can use?
Answer:
There can be a difference in the mechanism used by the shaver. Some poskim do not permit any electric shavers; some permit virtually all shavers, and some make a distinction in the mechanism. There has been much discussion over lift-and-cut shavers, and foil shavers. For details, see http://www.koshershaver.org/why.htm. Even according to the stringent opinions, one may use a trimmer, which leaves something of a stubble on the face.