Finally got my XDA-2 hooked up in my system today. I'll save more in depth sound impressions for later, but I'm really liking it so far. I'm using it as a dac and preamp replacing the preamp section of my RR2150, so keep that in mind when I post any comparisons. I'm using both a coax input from an old DVD player and the usb input from a computer, which requires you to download and install drivers from emotiva's website. The computer is running Vista, which has not been officially tested, but I've had not problems. So far, I am happy with the usb implementation as it is not noticeably different from the original CD through coax, although I haven't played around with the built-in sample rate converter. I really appreciate the implementation of the volume control; it has a very wide range, which comes in handy since, when using the RR2150's preamp, I did not have fine control of the volume through the remote at the levels I listen. I haven't tried out the headphone section yet, but I think this product is certainly more geared towards the speaker crowd in both form and function. In terms of sound, and only comparing from memory, I don't think this is as big of an improvement over the RR2150's DAC (which I actuall preferred to my old HRT MS II) as when I hooked up my HRT MS Pro in my same system, but even if this impression holds for me, the features of the XDA-2 will definitely make it a keeper for me.