"Call me an audio snob but I am deeply sceptical of $300 devices being able to perform at the level of mac based music server architectures, used by computer audiophiles the world over. "
Well, one is entitled to be skeptical but I suspect that one would be mistaken.
What is it exactly that makes a mac based music server architecture so special again for audiophiles?
Actually the DAC in the latest Squeezebox Touch specifically is rumored to be pretty good but I have not even tried it in that I had my DAC nailed down prior to going with the Squeeze devices.
A Mac based music server is fine. Squeezeserver runs on Macs, PCs, and other OSs, so you can use Squeeze players and your DAC of choice with a Mac music server.
But if the "mac based music server architecture" is so good, why use a third party DAC at all? Just use the one in the Mac and be done with it.