W30 it is...
The SD2 is warmer and has some more punch. Both are not very intimate and have a respectful distance to the listener, yet the SD2 has a more romantic presentation when it comes to closeness of voices.
So SD2 has some thicker upper bass and lusher voices, which I personally prefer.
Whereas the SD2 rolls off smoothly in the highs, the UERM shows more linear presence, but also has a peak that I noticed with the demo unit (could not be apparent with the custom).
My observation was that the UERM is very analytical whereas the SD2 is not. Personally, I'd prefer the UERM for Classical & Jazz and SD2 for everything else.
My audition of UERM was some months ago, I could feel differently today, so don't trust my opinion alone.