Or, the people who love the Bryston are listening a lot louder than the OP at levels that would clip the PA5. The Bryson 3B has three times the power.Most likely expectation bias, sunk cost fallacy, or loudness bias due to improper (or nonexistent) level matching.
A simple phone recording of both Amps loaded into freeware Deltawave would give us answers, but hardly anyone bothers to do even that, being content with their uncontrolled, sighted listening impressions which are inevitably biased and hence useless.
Rick "would could easily imagine clipping the PA5, but probably not at moderate levels in the near field" Denney