Ilija,
Good observation. I also noticed that Marek has a Behringer M802A mixer (I hope I recognised the right make). I do not own M802A, but I use a Behringer MX1804X (larger model with built-in effects and EQ) for connection my PCs and AV/multimedia equipment in my multimedia room. Overall the quality is not too bad, it is definitely not as quiet as Mackie CR-1604 VLZ that I use for keyboard/PA connections, but the Behringer MX1804X is decent and feature-rich for the low price (less than US$400) and very useful tool to me. My Behringer mixer has none of the problems that you mentioned through daily usage. I have not tested M802A and thus I cannot comment whether it is bad or not, but I have used Behringer Composer and its MX-1804X mixer and the quality is not bad at all. I know that some of the Behringer products are now manufactured in Mainland China and thus a bad association with quality in mind.
Paul Ip
from Texas