Holy crap. I switched a Bryston BP26 in place of my MOON P5 preamp, and the difference is astounding. Perhaps just a question of synergy, because the P5 is an excellent pre in its own right, but now I find the 4B-SST is definitely a keeper.
I had read a couple of reviews in European magazines where they basically were saying that the BP26 is truly an exceptional pre, and I have to agree. Looks stupid, in typical Bryston fashion, and certainly not nearly as good as the P5,but man does it play the music. More openness, clarity, better imaging, coherence, precision - you name it.