Well its been 2 months since I purchased my new 3B-sst. I never did return it for the 4B-sst which I should have gotten in the first place. Anyways I am powering 2 sets of speakers with it, my studio 100's v2 and B&W DM601-s3. And my 3B-st is powering 2 sets of rear speakers, Paradigm monitor 9's and studio 20's. With the 2 sets of speakers hooked to the sst the amp it has never clipped, so it has more than enough power. With my 100's hooked to the st previously the amp would clip occasionally at my regular volume.
Anyways the sst adds a dimension of smoothness to the highs that wasn't there with the st, for lack of a better term I'll call it 'airiness'. I was playing 'Rock in Rio' by Iron Maiden last night and I have never heard this concert sound so real, it was like being it the front row of the concert (this was on the cd version. I had the dvd version before which sounded awful even though it was in dts.) This airiness I've heard on other albums as well like 'Pulse' by Pink Floyd. But with the 'Rock in Rio' I can definitely say it is due to this amp.
The sst has given my system an elite sound, and each and everytime I sit down to listen I say to myself "God does that ever sound good!" The sst has set me back financially a good six months, but I would buy one again in a flash if the need arise.