Can't comment on the Arcam, I've heard them but not in my system so I will only say they seem pretty close to the Proceed but not quite as distinct (again not in my system so could be dependent on so much else)
As for the Proceed, I've owned most amps they have made at ne time or another, and have had Bryston's for a short time. The two are completely different animals to my ears. The Proceed is very neutral with great resolution, while I find the Bryston to be rough in the upper end, though great bass, the highs always turned me off to them. To me ear the Proceed is a far superior amp.