@OK-Guy, that's a tough question. In terms of innovation, one is made to be an all-in-one (including music storage and UI for playback), the other is a DAC/amp (with a very cool bespoke DAC implementation) without media storage. As for which one sounds better, it's the Hugo. The Hugo is one of the best DAC/amps I've ever heard, regardless of form factor, and I can't wait to use it as a DAC-only with some of my favorite desktop DACs.
Jude... big respect for answering that, it is now pretty obvious which way I'm going to go, ZX1>Hugo>CIEM's (I got to get me some full-sized headphones).