I opened a whole thread for it, I too find it quite underrated…
It also seems like I didn’t find this thread earlier, mainly because the model is called “TR-Amp” and the title for this topic is “TR-DAC”…
I think the main explanation as to why there is low interest, is because not many are ready to step their foot into something that seems too good to be true. It’s like an undiscovered territory that everyone is afraid to step into. It also doesn’t make much sense that people would prefer and rather buy Fiio with QC issues over a European manufactured device (with no QC issues and of build quality that you can literally use it as a weapon… Nokia 3310 vibes 
).