Concentrating just on GaN amps, the observations made for Atmosphere GaN monos may well be applied to a number of other GaN amps. I honestly can see no proof of superiority except that I read a number of subjective expressions. I readily believe that Atmosphere d amps sound wonderful, and would really like to know more on how much better are they than the other GaN amps. This thread, so far, didn’t help me in this. Too many subjective points of view.
How do you define "superiority"? Of course all you have read here are subjective opinions because the vast majority of people here either believe their opinion actually has relevance to those besides themselves or they believe the opinions of others have relevance to themselves. As I have said repeatedly, the only possible way to actually compare amplifiers in a way that can be logically and rationally valid is by looking at the specs. The specs won't tell you if you will like the sound, but they do provide useful data about the performance, design, and can give hints about the sound. As such, they are a good starting point. Any discussion outside of the measured performance is simply subjective opinion and a waste of one's time when it comes to how you will feel about the sound.
The only way to make any judgments of how you will judge the sound of an amp (or any other audio component) in your system, in your room, is to experience it first hand. The opinions of others, regardless of their experience, are not guaranteed to be yours no matter how hard they try to convince you that they "know" some mystical "truth" because they have been "listening to wire" for 40 years.