Hi Zachik, I can answer #1 based on my experience of owning both the U12 and a DI-20 (non-HE). Firstly, from a usability standpoint, the DI-20 is plug and play with the Amanero driver I previously installed for my R8. No issues with firmware, no glitches - just 100% music. The build of the DI-20 is much more robust and solid. I love the large display and the easy switching of functions. As far as the sound qualities, I find the U16 to be accurate, but dry in comparison to the DI-20. The U16 is quite good, but the DI-20 is much better and soundstage three-dimensionality, bottom-to-top extension, tightness of bass, musical flow, and body. I have about 500 hours on the DI-20 and the sound is still improving. I was listening to Autumn Leaves - Jacintha, and for the first time in my system, her voice was actually in front of the speaker plane. I had never experienced that before. Previously, I was able to get good depth and width of the soundstage, but all performers shared the same lateral plane. Last night was the first time on good recordings where the performer(s) were in front of the instruments, that I was able to get that 3-D realism of soundstage.