I have found one quality bearing, but it is a open bearing.
O well I don't mind the bearing is still in the motor, so dirt etc can get in.....
Without the rubber seals, a hose directed in the wrong place could easily allow water to make its way between the the hub cover and the controller housing and straight into the bearing, passing straight through it and ending up inside the main motor assembly.
I personally, would not choose to fit any bearing without rubber seals to my MPIII!
Even a quality bearing is unlikely to last very long once water and dirt gets into it.
Alan