Pretty good, I would like them to have a tighter tolerence on the motor shaft so you don't have to lean on the setscrew so much. I have drilled mine out for a larger setscrew and also use a lot of loctite when doing the installation so as to stop them coming loose and having an annoying 'clicking' sound start to happen in the rear setup. One other source of noise can be the bearings, which can work loose again causing a clicking sound but you should be checking this prior to riding anyway. The boards should be near silent when you ride them.