I have done EXTENSIVE listening to both of the amps you are considering, and chose the Bryston 4B-ST. (A friend owns the Aragon 8008, and I auditioned it in my system for over a month with a Bryston 4B-ST.) With my speakers (Vandersteen 3A Signatures with a pair of Vandy 2Wq subs), the Bryston is cleaner, more transparent and extended in the higher frequencies, and a bit more dynamic on transients than the Aragon. It also has prodigious bass-handling capability. (Note that nowhere in this comment have I said the Bryston is bright -- it is NOT. The 4B-ST is just barely on the warm side of neutral, with the 8008 a touch warmer yet.) Combine all this with a 20-year, unconditional, transferrable warranty and arguably the best service support in the industry, and Bryston is a tough act to beat.
With a different speaker combination, and in a different room than mine, I could certainly understand that someone might prefer the Aragon to the Bryston. If at all possible, you should audition both of these amps in your home so you can get an idea of how they work in YOUR system and listening environment.
