I only know of one bike with it on. I know for a fact they wish they went trubo instead.
I understand Vance and Hines isn't selling them right now, trying to get some bugs worked out of the system.
I also understand that the power maxes out at 140hp or so. There was a shop that tried to put a super charger on a BB, and actually lost horsepower. The Super Charger doens't flow enough to get air into the big jugs, and became a choke point for the intake of the motor.