I do feel it a very underrated amp, I think due to the fact that it DIY. Example the GSX MKII is highly regarded as the best SS amp but it simply a balance dynalo, a dynamite (balance dynahi is better in my opinion, moar power) is not mention much because it a DIY only amp.
I did some extensive research on both the Beta22 and Dynamite before deciding on which amp to get.
Ended with the Beta22 because it so flexible it can drive speakers (Great for HE-6) and has insane amount of power. The Dynamite was design for high impedance headphone. I have headphone of all different impedance so it was a no brainer.
Also, before I went amp hunting I was researching for the best amp for the HD800 because I wanted speaker like soundstage. Beta22 kept popping up. IMO of all the amp I tested, the beta22 offered the widest soundstage.