You can look up any reviews instead of just taking my word for it. Like I said, I've owned the bigger more powerful (on paper) headphone amps and this is just better plain and simple. Current drive and R2R are genuine advances in this area of DAC/Amp architecture in a compact size using high end SoCs.
I don't expect anyone to believe me as always, but until you have actually heard one then you basically have no basis for a comparison.
I know how it looks, and I was exactly the same, "how can something that small be good compared to a big powered desktop amp..." but like always, I buy stuff to try it out for myself and then return it if it's not up to scratch. My Amazon returns history is proof of this
I keep what is actually good, return what isn't. This is 100% the former.
I've been reviewing and using portable audio gear for long enough now to fairly easily tell different kit apart as well, it's obvious right away when something isn't quite right.