Just a point of order; the OP never said a word about energy savings... Sometimes a compressor is just a compressor.
Mobex,
I used to be the supplier of all soft starters for Sullair years ago, I assure you there is no problem with soft starting them. In fact some of the dealers insisted on supplying soft starters even if the user didn't ask for it because they got fewer call backs for mechanical problems.
Keith,
I've got a small plastic see-through model of a Sullair compressor. If you spin it fast enough with your fingers, you can feel it moving air. If I remember to, I'll bring it by some time.