Yes, I did have both the Opus 21 GNSC Reference briefly and Wadia 861SE GNSC for quite awhile. I now have the Bolder SB2 with Ultimate Nirvana supply and would never return to either one of the others, based on the value proposition. I'm sure I've posted on both before, so you might do a search there for more depth.
For the most part the Wadia GNSC was an extraordinary player, that revealed amazing detail and spatial information I didn't think possible in redbook CD. The Opus is just a more organic and smooth sounding piece at the expense of some of that inner information. Many would think the Wadia to be too much, but I think it was simply quite true to what was there. The Opus is one most could live with for a long time, not realizing there might be something as different and startling as the Wadia, though some might not think of the 861 as "better". It's all a matter of taste. FWIW Steve seemed to think the new 581 multiformat series may actually be a step backward from the 861 as the SE transport is no more. The Bolder is closer to the Opus than the Wadia, though the Nirvana upgrade seems to be getting closer with the amount of information it extracts - just amazing.
I wish I had a chance to hear a Lessloss as it's always been on my audition list, but never had the opportunity. The other on the shortlist in that league ought to be the Empirical Audio stuff. Hope this helps.
Tom