Odd...
It was a complete non-starter for me as the sound was ear-reamingly harsh: violins quite unlistenable, and cellos/basses rather anaemic. Also, I could hear the (CDROM-based) transport from the other end of the room, although they may have addressed that since.
Very interesting and a valid comment because I have long believed Resolution Audio's biggest issue is consistency between one unit to the next - in fact, I don't mind admitting that I'm on my third transport - the original had, as you say, that whine, and the second had the vibes. All is well with the third, but saying that a loading resistor blew causing a channel imbalance which has since been fixed. Ironically my dealer's unit has been trouble free. I'm not best pleased with my (now ex-) dealer for the hassles, especially as no loan machine was offered during my player's absences, but now my machine is fine at last.
Harsh sounds aren't what I've heard out of the Opus 21, however - I'm intrigued to find out what the rest of the system was when you listened to it, and what the mains was like. Whilst the Opus isn't as laid-back or mellow as some I've heard, it's a long way short of a Naim player in terms of its 'edginess' under less than ideal conditions. If anything, I'd suggest it errs on the side of smooth rather than harsh, but that's something which seems to be dependent on the support it sits on.
I am wondering if you've heard a 'dud' - my player, for all it's initial hassles (and to be fair, I was an early adopter) never sounded any less than thrilling, beating some of the following players that I heard en route:
Naim CDX w/wo XPS
Naim CDS2 w. XPS
Simaudio Moon Eclipse w/wo HDCD (two generations, you could say)
Simaudio Nove (I think that's what it was anyway)
Wadia 301 (I think that's the number)
Rega Jupiter
Musical Fidelity NuVista CD (retrospectively)
...and a couple of others I forget. My favourite (in terms of bang-for-the-buck), outside the Opus 21, was the CDX without XPS and the second generation Moon Eclipse was the easiest to listen to (a double edged sword; it was also easy to get bored but then perhaps by the same token that was a duff sample too)
It's supposed to be good in the PR&T stakes (although that generally passes me by) - may be a problem for the flatties though as it does very good imaging and soundstaging too (Sorry TopCat - just teasing).
Actually, it's great at the round earth stuff - it concedes a small amount of detail to the Moon Eclipse mkII, but otherwise it's very transparent, very tight in the bass, even-handed and never sounds harsh (despite Graham's experiences). Indeed, I'm happy to let anyone interested in hearing it pop round for a visit, just to show how good a player it really is.
All that said, on a good pressing of a good recording of great music, my LP12/Armageddon/Aro/Helikon still has the edge!
jtc