I have primarily only really invested in lowest noise and a very good DAC. Quality SSD drives for the unit in my listening room, manual power supply fan control gives me a unit that is simply not acoustically audible from my listening position. The media server is a linux based NAS box in another room. I am very Apple/iTunes centric as I simply hate dealing with Windows. I have no claims about better or worse sound quality (although the firewire port does let me use some DACs that sound better to me than the USB versions that I have tried). I find nothing that I can define as "wrong" and a whole lot that I can define as very "convenient" - including headless operation with an iPod as a remote control.
I think with high quality SSDs and a very, very quiet power supply (passively cooled?), $400 will not be that easy to hit. At least in Germany it wouldn't be.
Whenever I feel blue, I start breathing again.
There of course is a ton of garbage on the net about the sound quality of a DAW with WLAN vs gigabit ethernet, analog or digital power supplies, memory, manufacturer of hard drive, active ports.