I've been comparing the audio output from the Oppo 83 SE analog vs HDMI. After careful study, I can off these observations:
The analog output is clearly superior is timbre accuracy and tonality -- the midbass the midrange are fuller and better defined. In two channel listenings the soundstage is superior to HDMI getting back to the old stereo imaging coming from vinyl and MC pickups.
But in multichannel soundstage, especially with Masteraudio recordings HDMI takes imaging to an significant new level. The spacial resolution is dramatic on well recorded sources. Tinker Taylor Soldier Spy is a well nuanced example -- in one scene someone was walking in an upstairs room. I thought my wife was walking around upstairs -- the foot falls were discrete and spacially correct. The ambiance in the squash court was spot on. Complex scenes with groups of people resolved into the central dialog surrounded by discrete well focused side conversations.
So after over a year of tweaking and study I have to say both outputs have their place, but I don't enjoy the analog multichannel as much as the digital even with the former's more pleasing tonality because of the digital soundstage advantage. Two channel listening is better with the analog.
Oppo should be rolling out its new models by November of this year, and I will have to decide whether to spring for the upper model which will likely offer enhanced analog audio output. I may keep the 83SE for two channel, and go with the standard digital audio from the new player.