Well I started as skeptic, but whomever said there is not going back, was absolutely correct. The Lumin U1 mini made a bigger difference than i had expected over the old pc. My implementation is a usb harddrive as input and usb output to my chord dac. I will note that I have a intona usb 3.0 isolator in the path between the U1 and Qutest dac.
Lows are tighter, there is more soundstage, and it seems that the mids particularly vocals have a little more "space" around them. Great product and the app for the Ipad works great.