I have and heard some pretty good single DD, along with 2 IMRs. And let me tell you my findings:
Sennheiser IE600, $799, sounds miles better than Elan and Dark Matter. Except upper mids, which is a bit too much spicy and sounds unnatural. But it sets a standard for imaging and three dimensional stage - outstanding to say the least.
Meze Advar, $699, sounds better than Elan and DM in terms of spaciousness and imaging. Much better than DM in terms of Treble (well, anything is better than DM in terms of treble, even my Penon Vortex). Elan has the upper hand in bass, but Advar lower mid is much more organic than Elan, and not as overly full-bodied as DM. Female vocals are better on DM though.
Shanling MG600, $599, different tuning, not exactly better than Elan, more like equals, but definitely better than DM in terms of bass tightness and treble energy & extension. Mids are quite fine on them, better than Elan, different than DM.
FAudio Dark Sky, $1100, simply better than Elan and DM in all fields, hands down.
634EARS LOAK-T (CL) Cocobolo, $626, much more transparent and open sounding with a bigger stage than both Elan and DM. Although Elan and DM seems to have a touch more depth, and slightly better imaging on Elan. DM loses because of its overblown midbass.
From what little I heard of the Sennheiser IE900, again it's much better than both Elan and DM.
I am not much inclined to BA timbre. But discounting that personal preference, I can say that the top class iems truly perform their price's worth. For example - Sony IER-M9 and 64 Audio U12T. Both of them are miles and miles ahead of Elan and DM. Same goes for Vision Ears VE8, EVE20, QDC Anoe VX. I have heard them all, and they are all in their own distinct classes that Elan and DM cannot even hope to touch.
So, yes, the crazily priced iems that are out there, they do things better than Elan and DM very surely. Whether the price difference justifies that - now that is a question which is very personal for each individual. For me, it does till the level of may be $1500...but I do not see me buying iems costlier than that simply because I want a bit better sound.
Oh, to focus on the lower tier, Hiby Lasya and Penon Vortex - both of them sound very comparable with Splash Of Red, if not better in some aspects, while inferior in some. So to state that SOR is unmatchable in its specific price point would be wrong.
For me, IMR makes quite interesting IEMs, which are quite good for their price, but definitely does not play above their price. However, the insanely discounted price makes them that much desirable and worthy. For Elan, I might have felt paying a bit more justifiable, but not for DM.