I auditioned the Aquila III during this High End Munich 2023. The build and design are fantastic, the volume knob is a rotary encoder of sort with distinct steps and does not feel hollow like some of their competitors. There was enough power to easily drive Sennheiser HD820 and the Ananda Nano that they paired this one with.
Please take my impressions with grain of salts as the showfloor is not the best place to form impressions, but I found the Aquila III to have a slightly warmer tone with very good dynamics. The slight warmth and analogue-ness is usually what I expect from Yulong and it's present here again. I was listening to the Clock X1 mode, perhaps clock x2 would have a more "reference" take on sound. However, I preferred the sound on x1 enough to think that this might become one of the best all-in-one offerings under USD$1K.
I think you won't regret the purchase, at least based on my short impressions.