I used ARC tube amps for nearly 20 years and found ARC to give great service. However, I have gotten comparable or better service from several others, notably Stanalog Imports (van den Hul cartridge & phono equiptment importer), Pass Labs, McIntosh Labs, Classe, May Audio (van den Hul wire importer), and QS&D (Quad & Spendor speaker service).
Audio Research has the Best Customer Service
Not only does their stuff sound awesome! Smooth / Musical. They have the best customer service too! I picked up a CD-2 here on Audiogon (One of the nicest sounding players around). I called up ARC and asked if they had any left over Brochures on this model, I told her I picked up a second hand CD-2. The friendly Lady on the phone said I will have a look. This morning I got a brochure and a review in the mail. In the Past they also walked me threw biasing my amp for twenty minutes. This is a Brand to be proud of, I reccomend ARC highly to all!