1. The Bricasti, while being nearly the equal in simple aspects like noise floor (both amps had inaudible noise at the listening position) was able to eek out a bit more detail in things like instrumental timbre: such that differences between instruments which sound similar, were more clearly separated and distinguished from each other. The Bricasti also had an ever so slightly more natural tone noticeable specifically on voices (but likely present on instruments as well). I work with Sonore, and we exhibited at RMAF last year with this Bricasti amp and Vivid audio Kaya 45 speakers: this slightly more natural tone made vocal reproduction on the Kayas as clear, and real sounding as I have ever heard (being in the industry I hear a lot of high end systems). I did not get to hear the NC-400 through the Kaya 45s though... These differences were small, but they were big enough to notice, and to matter to an audiophile.
2. Having listened to many, many amplifiers, and many systems throughout my 20 years in the industry and being an audiophile since high school (with an audiophile Uncle and Father), I have learned, mostly, how to avoid allowing things like aesthetics to color my view of sound quality. That being said, certainly the build quality of the Bricasti products is impressive: I have seen audiophile products at the same price level which are not nearly as well built, right down to the quality of the screws used and things such as that; clearly this is an expensive component, but knowing something about what it costs to make things, it is fairly priced. whether it is "worth it" to an individual is a personal decision of course.
One thing I would note is that Bricasti amplifiers are designed to be good performers from an objective perspective, they measure pretty well. Stereophile has measurements of the M28 mono blocks on their site. I am no "objectivist" when it comes to the standard set of measurements, and unlike a lot of people who frequent this forum, I accept that the standard set of measurements does not tell everything about how a given audio component may sound. That does not put me in any "camp", and certainly I believe that the standard set of measurements are important to understand aspects of audio performance, but I feel we have not yet found all the measurements we need to fully describe every aspect of audio performance. I understand that the nature of Amir's site here is to push back against the "magical" claims of some audio products, and some audiophiles, and that is all well and good (and appreciated), but I would like to see a little more open mindedness towards the idea that perhaps what we really should be doing (scientifically) is looking for new measurements to describe the aspects of performance which the current standard set of measurements appear not to be able to do.
By all measures, for example, the NC-400 should sound "perfect" right? I mean, all noise and distortion products are at levels which are considered inaudible. So, how does one listen to the Purifi amp and hear that it sounds "better"? If that is true, we must be missing something with our measures.
If I had money to burn, I would buy one of these Bricasti M25 amps, and be very happy with it. At the same time I would also make a substantial contribution to charity, perhaps to feeding the poor, to somewhat offset the conspicuous consumption.
Anyway, I am currently collecting parts and working on getting a chassis to build up my Purifi amp here. Then I am going to re-cap the NC-400 boards (they have been on 24/7 for about 6 years now...) with some long life Rubycon ZLH caps.