I've had several including my PC and MAC as a source (my first source). I've tried some ChiFi (Suncos @ $500) and a sound card plugged into my first decent DAC (PS Audio Perfect Wave). I got talked into a PS Audio AirLens and have been very happy with it. It's been trouble free unlike my former purchases.
I think the reason it sounds so good is it's isolation technology. From their website which Audiogoon won't allow links to:
Unfortunately, connecting your sensitive DAC to the noise generated by computers, routers, NAS, local networks, and modems via either WiFi or Ethernet cable is not a great-sounding solution to bringing high-performance audio into your listening environment. The PS Audio AirLens™ completely eliminates the problems of noise, jitter, and EMI influences through complete galvanic isolation and perfect reclocking of the digital audio signal. You’ve not yet heard how great streaming can sound until you experience audio through the AirLens.
Prices have dropped to $1,600 with a free 30 day return policy if you don't like it.
So far I'm really happy with it. However because the technology obeys Moors Law you can expect 2X the quality at 1/2 the price in 18 months or so.