Funny how all the reviews & all the users report how good the DAC sounds - even the two that supplied their DACs to Amir.
I've toured the ISO-DAC & ISO-SPDIF on PinkFishMedia UK forum & again unanimous reports of great sound
Are you implying that all DACs sound the same, since blind testing shows no difference in the sound of well designed DACs - and even electronics disasters like your Ciúnas units can sound good?
(Why does the term "Dunning-Kruger" keep popping into my mind as I read and participate in this astounding thread.)