I just sold a 4B SST, and currently use a 3B SST (purchased cheap) in my small listening room. Personally, in that room I could'nt hear an audible difference between these two amps. So I sold the more expensive/bigger one to invest the money into an LED TV. I did hear that the 4B SST2 does not sound any different then the older 4B SST, but from what Robert is saying, I guess the differences are beyond subtle (to his ears). If I ever go back up the Bryston chain I will go for the 7B SST2's, and of course I will have a dedicated sound room built for it in my basement, but for now the 3B SST is sufficient for my little 10x10 den/mancave.