I have recently purchased the Bryston 4B cubed amp. Bryston has hit the mark with the cubed series. I was running Musician III Mk2 with all available upgrades in mono block.
The 4B3 has a way of control of my Usher be-20 diamond woofers that I only heard with Belles MB-500 mono blocks $15,000.00 USD new. Being from Texas, those MB-500s were not a option due to the heat generation of that design.
Called Bryston after purchased and asked if I could do better than the 4B3 sound wise, they reviewed my speaker specs and said no!!! How's that for customer service. Going up the Bryston chain would only increase power output to the speaker, sound quality would remain the same. As you see this is a company that puts the best of their technical expertise in all the cubed models, you choose your power requirements for your speakers and system. This is my first Bryston purchase, but most likely not my last. Outstanding Job!!!!