Audio Research service

I have owned a number of pieces and still do. The first amp I bought brand new started sounding bad in one channel after 3 months. Upon calling ARC Leonard says" I don't know you'll have to ship it back". The ONE tube that was replaced cost $200 in shipping and 3 hours in my time lugging the box to fed express.
I love the sound so I upgrade to a better amp: VT-100 tube replacement after 2 years of very light use was $1300. A bit annoyed I immediately sell this amp and guess what it doesn't work when the buyer plays it for the first time. My ears are still ringing from the buyer's yelling. Yes ARC eventually fixed it.
The equipment is very good but there are considerable concerns with the cost of maintenance and EASE of maintenance.

To re-tube a VT100 is $1300?

To retube my VT100 MKIII from ARC is $500. Maybe that's only the power tubes. And you can certainly get them somewhere other than ARC for less. The other tubes are 6H30's which shouldn't need replacement for years. So that $1300 sounds mighty steep!

ARC service is as good as it gets.

In addition to my previous response, you probably will never need service. As it states in the owners manual
"this amp will bring musically satisfing results as long as you care to own it". Enough said.