AUDIO RESEARCH VS VTL

Unfortunately, there is no "king". It all depends on all your associated gear, room and preferences.

I’ve never owned an AR amp, only a pre. I have owned the MB-125 (first gen) and absolutely loved those monos. Sold them, missed them a few years later, and bought the first gen MB-185.

AR customer service was fantastic. 

i got a solid three paragraphs from Jonathan Carr on ideas to improve my Delos. My ARC Ref5se just crossed 5k trouble free listening hours…magic… And ARC answers the phone….

Most probably order a Etna - Lambda next week for the SOTA in the reference system.

Audio full of good people

Now IF Oyaide….WTF

I try avoiding these conversations but both of these companies have crap service and the ARC GS150 I tried was not that great and for the asking price a flat out ripoff.  I had MB185 signatures long ago that couldn’t maintain bias so I moved on from them.  Asking which brand is better is a loaded question especially for these forums that seem to bring out the nasties from some of us on these forums.  Brands like VAC, Quick Silver and a few other offer some really good values on the used side for high power tube amplifiers.

💩 thread right here...

William Zane Johnson invented the modern tube amplifier and started a company called Audio Research. I have owned 3 ARC power amplifiers including 250SE monoblocks and 160M monoblocks. Audio Research has been extremely responsible and have even repaired out of warranty used amplifiers for me free-of-charge. 

If you have a good relationship with an ARC dealer, you can get great deals on demo models at a substantial discount. It is indicative of the groupthink on social media in which folks believe that every company has to cater to their every whim.  All of these niche companies are very small, so do not expect instant, on-demand customer service like you would get from Amazon or McIntosh.

In terms of sound, it depends on your system. I have tried McIntosh, VTL, VAC and CJ tube amps in my system and none of them sound as good as ARC tube amps. My system has an Esoteric K-01XD source, Luxman CL1000 preamplifier, and Wilson Audio Sasha DAW speakers. I think that ARC power amps work well with Wilson Audio speakers.

I think the OP posed a somewhat limited question. Are you trying to decide between buying one or the other? There are many great tube amplifiers, and there is no absolute answer to your question.