For me after like 15h listening that feels like something I can second.Don't know how to calculate Naturalness, but overall its balanced and nothing feels out of the place.
Time to time I can't escape the feeling that the mid and lower base is now better than before, low volume listening wasn't this good with other amps for me in the same setup.
The biggest difference vs the WiiM amp it replaced for me is that low listening volumes are definitely better and (maybe not surprisingly) likely thanks to the higher power output it holds up better at really high volumes, but both of these can of course also be due to me changing to a Wiim Ultra at the same time so it's not a great review situation I'm in.
Overall I'm super happy and felt like a good upgrade and something that matches my speakers (Polk R500) a lot better than the WiiM amp even if I'm still mighty impressed with that little device.