For years I never did get the Avalon presentation at shows but in the first ten minutes of listening to my standard Eidolons at home I got off the merrygoround.
I've herd them powered by Ayre V-1xe stereo, MFA D70 stereo, VAC Phi200s, freshend up MFA M-200s, and Carver VTA180s all off their 4 ohm taps. Unfortunatly, I was unable to do side by sides comparisons of the tube mono's.
The D70 demonstrated the need for more power for listening approaching realistic levels. I agree with siddh these are revealing speakers were everything matters. Even though the three high powerd tube mono's each have their own presentation my poor sonic memory prevents me from picking a favorite so I picked the ones made in America. Does that help?
Use the spikes, that port needs to breath.