Bryston or Pass Labs

I know this is a old thread but I'm finding myself with a loaner 4b3 which I like very much but I also like what I read about Pass and am contemplating buying on approval from Reno or finding a used unit.  I'll note here that if you can go to the X150.8 that amp actually competes price wise with the 4b3.  The Pass products are generally grossly underrated power wise and perform 25-35% higher than their stated output.  So while the x150.8 is not as underpowered as you think it might be in comparison to the 4b3.  The 4b3 is FAR FAR more musical to me than the "squared" series, much more delicate upper midrange and highs, beautifully detailed but not etched.  It still is a little lacking in the presence department but only slightly and my suspicion is that's where the Pass will exceed the Bryston.  The Bryston is however an exceedingly "fast" amp without being etched and is also totally dual mono with two stacked transformers (one for each channel).  The build quality is astonishing and the thing can just put out a huge amount of power with no compression.  I can easily listen to 110 db peaks on large orchestra recordings on the Bryston with no compression or odd things going on at all so I am impressed.  Any further thoughts from anyone are welcome.  My front end is largely digital (Bryston BDP-1) using Audirvana and a tubed Aesthetix Janus preamp with Thiel 2.4s.

I guess I'm the only one who would select based on which amp I had a hope of moving it upstairs on my own.  Actually, I'd probably go with a 3B3 on that basis, as long as we are sticking with class A/B.

No l have not however l have heard the 3bst with a pair of maggies.