Never had a problem with my Pass while I owned it. But have received excellent support from the following company's: Krell (Patrick is great), BAT, Channel Islands, Thiel come to mind in particular for providing exceptional support and timely feedback, either by phone or e-mail. Other notables where McIntosh and B&K. Most recently, I have received great after sales support from Aesthetix, both the company and the distributor here in the States. Kora and Audio Aero (both French companies) on the other hand were very much lacking of decent customer support.
More importantly here I think is the fact that there are units in the field that do not perform properly or to their full potential. It is sometimes difficult to determine whether this is a matter of personal taste or an actual problem with the component. Knowing that pieces ship from the factory out of spec, imagine how much more likely it is that they are being sold used "out of spec". Recall the reviews the rags have done only to report that their test sample was out of spec or not functioning properly. If the manufacturers can't get an in spec item to a reviewer, imagine how poor their quality controls are for the everyday customer.
I have purchased equipment in the past with print outs of the actual testing procedure for the individual component that I received. In this industry, at the higher end price points, it would seem that this should be standard protocol. I believe it was an ARC preamp that came with the hand written pre-ship test results. Also I think my very old Golden Tube Audio SE 40.