My apologies - I have not seen or heard the UX-3se, I meant simply to address that I feel the Standard DV-50 with an external video processor was significantly better than even a DV-50S in video quality in my system. Given that the "S" upgrade is $500 plus shipping, it is not that much more dough to stick with the standard DV-50 and add an external video box. Plus, you might get some extra video flexibility to boot.
Many, me included, feel the DV-50(and the S) falls short on the video side of things on its own. However, by adding an external video processor, I feel I am not compromising in the slightest on video.
And then there's the audio...just very nice!