Manufacturers with Excellent customer service

Not a manufacturer, but Kevin Deal at Upscale Audio. I also second Vlad Bazelkov at Audio Mirror. And add Kara Chaffe of Dehavilland. Also Egglestonworks (speakers). I have dealt directly with all of these folks and the service was first-class, as expected. 

PS Audio and Pass Labs have impressed me greatly. Very responsive and clearly want to make sure you are happy as a user.

Bryston has been great.  Have never had a problem, but many questions and all answered quickly.

Surprised Keith Herron hasn’t shown up yet—the best! Also great experience with LTA and Lou at Daedalus. My recent purchase with Paulo at Sempersonus, maker of a very fine idler-type turntable was remarkably pleasant and professional. All wonderful guys truly dedicated to their craft and clients.

Indeed, Upscale Audio (Kevin Deal and all of the employees) are exemplary of how professional help in this industry should be.

My experience with Balanced Audio Technology was by far the best I have ever had with any brand of product, no matter the industry.  

Sub Zero impressed me as well (kitchen refrigerator) with excellent customer service.  But my experience with BAT has been the absolute best.