Any Bryston 4B3 amp owners out there?

Thanks Elizabeth. If I buy Bryston, I'd buy new from Audio Advisor and they are authorized. 
I'm glad that you're happy with your amp. Would you be willing to share what you're using it with, especially your speakers?

I find the Cubed and BSST2 amplifiers to sound significantly different. I strongly prefer the Cubed sound in direct comparisons, but I have met people who prefer the BSST2 sound instead also in direct comparisons.

nekoaudio,
It's my understanding that the biggest difference between the two happens at the input stage. The cubed input has dramatic refinements/changes and this is where most of the magic happens with respect to musicality. All of the hybrid amps I've seen have tubes at the input for that season.
I've been overwhelmed with opinions on two different threads. All but a few have been valuable and insightful. I've come to the conclusion that I'm going with Bryston. If I don't like it, I can return it. The Pass Labs, Simaudio, ML, etc will still show up used. Right now, I find no more pleasure in the buying/selling of equipment and the tweaking with cords/cables and the like. It's time to just enjoy the music and I hope the 4B3 is the missing link.

I used to own a 4b3 for about a month or so, did not find that it was a good match for my Rethm Saadhana speakers. I found it too blend and too mechanical sounding and a little too colourful for my taste.  It was also pulling to the left a little which I found strange, and I noticed that when I switched from Kharmas to Rethm (it was pulling to the left with Rethm).  My only explanation was that I did not notice this with Kharma since they were 89db and Rethm are more sensitive at 103db. Anyways I switched to an Italian brand and my system sang. Just my two cents.