Highest BUILD quality tube amps?

I have a McIntosh MC275 now and it is a monster in every way. The only flaw is the lettering on the sides as it always seems to rub off when you lift up the unit. 

Before that I used a pair of MC30s for nearly 20 years. I bought them used from the estate of the original owner, who told me he used it everyday and was sure he had never once replaced a tube. He had them from 1961 to 1993. Crazy. And I hooked them up and enjoyed the hell out of them for another 8 years before I bought new tubes.

Anyway, hope that answers your build question!

Conrad-Johnson. I’m surprised there is so little mention here. I’ve owned their products for more than thirty years with no problems whatsoever.
The availability of service is a huge issue for some of these brands. c-j will service anything they’ve ever made, not so with many including Audio Research. All hand wired here in Virginia. Extremely high quality parts throughout... an important part of their value proposition. And due to theses factors, c-j products retain their resale value. Oh yes, they sound amazing as well. In fact, when I was upgrading some years ago, Lew Johnson bought my old EF1 phono preamp for his own use.

I have had VTL MB-450 Series III for many years with no service required.  They sound great and with the Auto Bias function you just turn them on and listen......

Not the prettiest in the room but another + for Decware.