FWIW, I've worked on many Bryston 3B and 4B amps. While under warranty, most customers that we dealt with simply didn't want the downtime to ship the amp to Bryston and back, so we did the work locally in Vancouver.
Back then (1991 to 1995 when I owned the repair shop), Brystons were a well designed, well thought out amp. There was absolutely nothing within the amps that made them worth about $2200 retail CDN for the 4B though. I always thought that Bryston added $500-700 to the price of another typical comparable amp to cover the warranty.
Now, I had an old sales rep get in four 3Bs on trade on day, and he took two and I took two. They were about 18 1/2 years old. I tested mine and sold them on eBay. He sent his to Bryston, where they refurbished them. Since the amps were older, they did every mod/upgrade since the time they were made, changed the power switches, and called him to ask if for a very reasonable sum of money he wanted the two faceplates matched (his were nicotine stained as they came out of a bar), and they changed all the main filter caps.
Total price was $160 incl return shipping for both, sent back in factory original boxes, with the hand written spec sheet on top of each amp. He was tickled pink. Obviously the construction of the later Brystons are completely different than the older 4Bs, and I still find them a solid amp.
( I won't post how we took his amps and blind tested them against a $300 Korean made Inter M amp using an A/B switch, and how 2 out of 3 times he picked the Korean amp as sounding better...