As I'm starting to set up a music server I'd like a "real" answer to this as well. My plan is to store music files on a NAS and feed analog to my preamp with a Benchmark DAC1 USB but am struggling with my choice of "middle tier". Sound quality and the ability to access my library with reasonable ease are my primary objectives.
To those who assert that one platform is better than another, is it a question of how the ones and zeros are retrieved and sent to the DAC? Is it a question of jitter? Are there more "artifacts" (e.g. noise) sent from a PC than from a Mac? And is this the fault of the OS, the audio software or something with the hardware itself? If any of these are the case is it better to go with a dedicated appliance (Sonos, Slim or whatever)?
I am a PC guy and work with Wintel boxes as part of my job as a data architect but if a Mac Mini would SOUND better than a PC or appliance and I could fit it into my network and I don't have to use a monitor or laptop to control it, I'll use one. But I'm still searching for a technical reason why one is better than the other.
I have spent a little time in recording studios, mostly at the business end of the microphones. My impression as to why Macs are more common in music is that for so long they were the only game in town and so much easier for non-geeks to use.