For what it's worth, Richard Hardesty's Audio Perfectionist has just published an extensive comparative review of the VTL 7.5 v2, Esthetix Callisto Signature with twin external PS, and the ARC Ref 3. I do not have access to the complete article, but have been told Mr. Hardesty appears to have an overall preference for the Ref 3 over the other two devices. His final comment on the Ref 3 is:
Ive heard preamps that have a little more of this and a little more of that. But none thats as complete, top to bottom, or as satisfying in its presentation of the entire musical picture, weaving
each distinctive element of music into a coherent whole. The Ref 3 goes beyond hi-fi; its a 21
st
century classic from ARC.
G.