Opus 21 vs Esoteric X-3se

Well, the "running direct" question is a completely different discussion than the quality of digital playback between the two players. In my system, I prefer using a preamp, though I know many run the Opus direct. As with selecting any preamp, you'll need to look at impedance matching, required gain, etc.

I own the GNSC modded Opus and love it. I have heard the Esoteric (not in my system) and would agree with Arbuckle's assessment. However, as the old saying goes, "the devil is in the details". I think the detail level of the Esoteric really puts the pressue on your upstream components to keep up, whereas the Opus is likely more synergistic with a broader range of systems.