The ARC Ref 2 I'm currently using was a big improvement on the solid state Classe preamp I had been using. The Ref 2 I've owned for over a decade, it is definitely not lean tonally; if anything, it's slightly on the warm and "tubey" side.
I've inserted an Audio Research VT100 into this system as an experiment. The VT100 is vintage 1995 or so but has been updated with new caps and a set of KT120 output tubes. Sounds very good, but has more fan noise than I expected.
So at a crossroads presently.