Got mine on Friday! It's too early to post firm impressions as I would like to spend some time with the DAC (and let it settle a bit) and ultimately avoid mind tricks when auditioning the new HiFi toys
It does have quite unique and surprising sound trait. I could pick this DAC easily among the crowd! No trace of digital harshness with quite extended and detailed low end and super imaging (most surprisingly depth). It's musical too. Very little congestion when dealing with complex music passages. USB converter is first rate (really black, noise free background) and I find it clearly better then Coax connection from M2Tech HiFace2. It's very relaxed presentation and a bit on the lean side but definitely fatigue free - apart from the fact that S16 is very detailed. I've almost fall asleep last night with the music on, so that's a good sign. Headphone output is very useful. As I didn't have my HD600 handy, did managed to quickly audition UltraSone Pro 900 yesterday and 50-60 volume is plenty. As Pro 900 is a bit V shaped I didn't have much trouble with brightness (confirming that S16 is not harsh) but treble detail extraction and bass extension itself were phenomenal. Will test midrange when HD600 is back as they are very mid-centric.
Surely, there is no need for external PSU as integrated one is of high quality and that's big plus in my view. Build quality is very good. It feels solid when handling. S16 is a bit bigger that expected but still within the acceptable compact norm. Volume dial is a bit wobbly but with quite useful and linear volume control. Speaking of volume control, S16 is based on asymmetric design so that headphone section is separated form the analogue output stage - so no pre-amp on analogue outputs. Honestly, at this price level is rare to find a DAC with integrated pre-amp of acceptable quality. You are much better off pairing S16 with dedicated pre-amp.. Drivers are stable (with ASIO support too) and based on stock XMOS development platform.
I do have some quirks with the balanced (XLR) output. Not sure if Aune implemented negative attenuators (sounds like -6dB) in the balanced out section or it's input sensitivity on my amp ... but XLR volume level is significantly lower compared to unbalanced RCA outputs, so with the external amp I have to dial-in the volume more up north.
LCD display is very nice btw! It's very elegant, not bright and with relatively large fonts for easy reading. Didn't have time to play with the available filters, selectable by long pressing the volume dial.
Couple of pictures: