Track and IEM specific.
PCM reminds me of Class AB mode. It’s upsampling (ROON has a similar functionality). Mids and vocals more forward, but not necessarily more natural. DSD is more laid back, holographic with circumferential soundstage. I find it sounds closer to ‘off’ in natural timbre but as you say, has more presence.
I haven’t done an extensive test to see if the track quality also affects the results. It got to the point I changed my mind which I preferred depending on mood, track, IEM and so many variables it did my head in. Sometimes having options not always a good thing.
For the moment, I prefer DSD.