As one of the retards who chose to BUY the Amarra software and hardware with MONEY, I can say that I spent more time researching and considering those purchases than probably any other audio purchase I have made. I happen to live nearby their offices, so I met with the head of Sonic Studios/Amarra a couple of times, I got an early copy of the software for demo (with the dreaded iLok), I got a demo Amarra 4 to bring to a couple of meets including CanJam, and I compared the output of both in numerous ways. I also got JP and Ric and others to check it out and comment about it, and I took their similarly positive reactions to mean something. I then did more research and reading and made my decision. I've written about it numerous times on this site in the past.
I have no doubt that the SQ I get from Amarra is improved over iTunes on its own, and from what I know about how it is built and what it is doing makes sense to me. I am not in a position to try to explain it to you other than what I have written elsewhere on this site. I don't care whether you need to have some kind of empirical proof for you to believe something works or is worth money, and I cannot provide that to you anyway.
If you think there is a free/cheap/self-programmed way to get as good or better sound out of your computer, then have at it. But you can take your smug self-righteousness and your defensiveness about your PC and go fuck yourself with it.