By now you've probably read every forum and pro review, and their reader-comments, for both units. If the obvious diffs between the two are not show stoppers, the biggest diffs between them as I see it (and nobody's talking about) are:
o Audio DAC: 975's truncation of 192k digital signals down to 96k for processing. For audiophiles with their entire collection ripped to a lossless format this should be a huge consideration. This is what the Emo sales person explained to me. (If this is not true, or it's a sales ploy capitalizing on a technicality w/ no downside - I want to know about it!)
o Emo's lack of HD video up scaling. This is a pretty big difference between the two and could be very important to some.
I've read that the 975 is warmer sounding than the umc-200; or, perhaps the much-200 is more revealing?