I didn't see anything posted anywhere in this thread about ARC, but thought I'd comment on it:
@fsonicsmith wrote:
Audio Research Corp will not repair their solid state amps. They say it is not possible.
Pyramid Audio repaired my D400mkii, which ARC says is a very heavy and expensive paperweight if the power caps go bad. (un-serviceable). It works great now, but it's a PITA to deal with from a repair tech perspective (power caps are directly soldered to the boards). But that situation addresses a point brought up in this thread...barring a major malfunction, most equipment can be repaired if someone has the knowledge and/or skill.
Also, I happened to stop by @kchamber's place this weekend to pick up some Aragon gear he worked on and he had the aforementioned DNA-1 in his work area. The input boards are repairable as he and I talked about what needed to be done (time intensive). Since Kevin is local enough to me, I for one would feel fine picking up up a DNA-1 amp and having him work his magic (as he has for a few other pieces of my equipment).
If one doesn't have access to a good tech, caveat emptor (as they say)
So, outside of something catastrophic, if you can find a competent tech one should have no fear of an amp being inoperable.