I just tried viewing some videos in DV (on the LG TV app) and HDR (on Xbox One X app). I didn't think I'd see any difference at all, I'm definitely not much of a video 'purist'.
Lost in Space: There was a surprising difference here. The HDR looked fine, but switching to the DV it was far richer. As if it had a different gamma; the whites and blues really 'popped' in the LG app whereas in the XB1X app it appeared a bit more washed out, with a more yellow/brown palette?
Marco Polo: Less difference here (possibly because the colours of most terrain/buildings were yellow / brown palette anyway). I'd have to see them side-by-side, but IMO the DV was still slightly better.
So, based on a quick, unprofessional, non side-by-side comparison, the DV definitely looks better.
I can't rule out problems in individual encodings or problems with the XB1X Netflix app (I've read it can have some problems with HDR).