The D18 is my first exposure to the Yulong product. Both the sound and build quality of this DAC exceed my expectation,which gives me so much confidence in the Yulong product. Consequently I purchased the U18 so that I can use the USB of my MacBook Pro as the music source source. Now, I am quite happy with my little set up, which do not cost me an arm and a leg like similar products. May do more business with Yulong in the future.