My Herron VTSP-1A, as well as my former Air Tight ATC-1, and my former Supratek Syrah. All fantastically musical and transparent, with great life and also fantastic frequency extension. Also the Herron is the quietest tubed preamp I've ever heard. Hope that helps you.
I agree with Jond. I chose my Herron VTSP-1A/166 over the Conrad-Johnson Premier 17 LS2. In fact it wasn't even a contest, I thought. It's much better than my old Krell KRC-3 and Musical Fidelity A308cr, and those aren't slouchs by any means.
I haven't heard the most recent models.I can only relate to my past experiences.The CAT MK3 was incredible indeed for musicality.I have not seen very many of these for sale used.It must be a real keeper.Also the older ARC SP-11 was a real breakthrough product.