I've owned three B&K's over the last 15 years and have been happy with their overall tone and image. Very smooth and very sweet sounding. I used them for magnapan 1.6's, B&W NT6 and soliloquy 5.3's. The first two are power hungry speakers that the B&K drove very well. However, in recently comparing my 4420 to a relative underdog, NAD216thx amp, it lacked the detail that I am wanting from introducing better cables and interconnects.
I honestly had a fantastic experience when I took two of these NAD amps and ran them bridged to mono, one for each channel. In that configuration the NAD's had comparable ratings. The soliloquy 5.3's that have a silk dome tweaters. They have an built-in smooth sound (sort like a proac speaker) in comparison to the B&W or Paradigm metalic tweeter. With these speakers, the separation of voice, piano, percussion and horns on something like Diana Krall- where favorable to my ear over the smoother image of the B&K.
I remember very fondly that the B&K had a very good affect with the B&W speakers though. Those speakers were very fast and crisp, so the B&K smoothed them out slightly, and the image was big and coherent. And, as I mentioned before, the high current of the 4420 just absolutely opened them up! They just would get louder and stronger the more I pushed them.
If you're still with me I'm sorry I've never auditioned the Bryston, but if warrantee is a issue, I recently sent my 4420 back to B&K and for $100 they went through it 100% and sent it back to me in their words, "better than new".