Like I said, in direct comparison against most dual ESS DAC I have in my collection, the AFUL is not edgy in the higher frequencies. Using the same IEM, in tracks that are sibilant, I hear milder to no sibilance with Snowy Night. In that sense, it is indeed "sterile." It should be noted that such "softening" is also there with Chord Mojo2 (from memory) and Questyle M15, so I think it is an advantage.
At the same time, this dongle does not intensify the lower midrange (adding warmth) or adding midbass punch like my DX300 with stock Amp 11 Mk1 or my old Shanling M6 Ultra. When I use bass cannon IEMs from FatFreq (Scarlet Mini and Maestro Mini), the amount of bass I hear from Snowy Night is noticeably less than from my DX300, though by no mean killing the bass response.
I say it is a neutral dongle with slight warm touch, just like AFUL own IEM to pair with it, the Magic One.
What I like about this dongle is the sense of space. My major complaint about the FiiO dual ESS DACs (nothing against FiiO, it's just that I have done A/B tests yesterday so they are fresh on my mind) and Topping G5's ESS DAC is that they sound 2D. When I listen to the same orchestral recording, the Chord Mojo2, Snowy Night, and M15 properly convey the sense of depth (near to far) and height (low to high), whilst the FiiO and Topping are mostly left to right. The KA17 can have depth when turning the desktop mode, but it would drain battery relatively quickly.
Tbh, I went to audio store yesterday fully prepared to buy either M15 or KA17, but I left with only a new lightning to USB-C cable for my Snowy Night.