Ray Samuels B52 vs. other tube preamps?

Could anyone comment on the sound (as a preamp) of Ray Samuels' B52 vs. other tube preamps at any price point? The B52 is wonderful as a headphone amp, but I wanted someone's opinion of it as a preamp in a good system, and how it sounds vs. good preamps from ARC, CJ, Atmasphere, Joule, etc.
Thanks in advance.