Mike,
All is a matter of taste and preference and we have opinions always bonded to them. Perhaps I was not clear enough.
Many people consider that as soon as an amplifier does not have the nasty characteristics of sound of some typical solid state it immediately sounds as tubes. I have found that most tube electronics when properly matched have some intrinsic characteristics that differ enough from the DartZeel sound to say DartZeeel does not sound like tubes. I currently have conrad johnson, audio research and jadis amplifiers in my room, as well as the NH108 and do not find it to have tube character. It is better than that - it has its own character!
Perhaps my nitpick is due to the desire of listening to equipment achieving its full potential. BTW, I also raise my eyebrows when people compare the 8550 to the NS18-NH108 combo ...
I enjoy a lot reading Michael Fremer on audio - mostly his comments and theoretical analysis. I have talked to him, he is a very knowledgeable and enthusiastic person. But surely he is not my reference concerning equipment compatibility.