On 3 of them the fans crapped out, I started a thread here detailing my fix: Anybody got a source for replacement chinese chiller fans?
One of them the compressor failed spectacularly, blowing out an electrical connection and venting refrigerant and oil all over the top of the compressor and lower section of the rotovap. Have a new compressor I have not yet had a chance to install for that one, need to pick up some R404 to refill it once I’ve got the compressor lines soldered up and get it wired in.