After today I can confirm what you say. I love the UD-501.. its excellent in its own respects, but I had a chance to demo the ADI-2 today and definitely, I could tell right away that it was an upgrade. The width and detail of the presentation was apparent.. super clean, almost effortless. The fact that you can dial in EQ nevermind for each output? Man.. that is nice. Although I've found ways to accomplish this software side, its such a nice feature and the UX well thought out, that it makes it almost too obvious of an upgrade. Tested with Atticus and R1 in the store.. found that I had to crank the R1 a bit high (-7.0) before it started to get too hot, but the quality was there just the same. Would be interested to see how it plays with the G109, but in any event, I'm now a believer. Thinking I will grab one and demo for a longer period.. have no doubts that it will all end with me pulling the trigger.