The best tube poweramp. . What do you think about ?

Buying^^^

The Decware Zen TORII MKIV with KT77 tubes 25 watts of pure bliss.

AtmaSphere OTL?  The M60 for modest power requirements, the MA-1 on up for power-hungry speakers.  Stunning performance and rock-solid reliability.

VAC may be a contender as well--it's been too long since I've heard one, but the old ones were outstanding and I'm guessing they've only gotten better.

I have to admit bias(pun intended) since the Melos amps were designed by good friends. But monoblocks putting out a rated 400 watts(they actually put out more) in triode using only 4 output tubes is very imposing. I might add that they had a very high damping factor for tube amps thus greatly reducing the frequency response variation of tube amps into reactive loads. 

I use a Dennis Had built 45 SET, Cornwall speakers and LOVE it.............