A lot of people characterize Bryston's sonic signature in different ways - I've heard it called bright, warm, grainy, liquid, and so on.
IMO Bryston isn't any of these things. What they're hearing is the Bryston letting through whatever it's fed and/or the speakers.
You may hear brightness. You may hear a distant sound. I'm not a Bryston apologist, but I'd be willing to bet that if you're hearing things you don't want to hear, it's something else in the system. If it doesn't work out right, I'd look at the source and/or the preamp next. If there's a very small amount of an undesirable trait, the cables.
The reason why I've owned my B60 for so long and will never get rid of it is that it gets out of the way better than anything else I've heard/can afford. Whatever changes I've made in my system have always been easily audible. Since owning my B60, I've changed every component and cable and heard differences every time.
I should clarify that the B60 didn't make me change everything. It was the first piece I bought after I decided I wanted a total system upgrade. With a lot of amplification, there's always a sonic quality that remains whenever you change other things. With my B60, there's no character that's constantly there that I can detect. With other amps, when I made source changes, the differences were minimal or marginal at best, with my B60, the differences are very apparent.