I have not heard the Mojo. But I heard the chord Hugo in a nice system just yesterday. It sounded just the opposite.
Tight, fast and detailed bass, Great dynamics, Musical and transparent.
What was the setup in which you heard the Mojo ?
Mojo (amp+dac) with PC USB + Foobar - Ok sounding. Clean, black background. Timid bass, not enough resolving to reveal characteristics.
Mojo (as DAC) with PC USB + 6SN7 OTL tube amp + Foobar - Sucked big time. Slow gooey bass.
Mojo (as DAC+amp) + USB interconnect to phone - Slow and veiled.
Mojo in the context of portable setups is perhaps good sounding as most of the other portable stuff I've heard (Fiio X series, A&K jr,70,300, Sony ZX100 ) sucked.
However, in absolute terms the mojo is just about average.
On the other hand in terms of tone/timbre the Mojo is more agreeable than the Hugo. I've heard hugo only once (with HD800 unmodded) and could not tolerate it for more than couple of minutes. Treble glare, poor depth/headstage to name a few. Although it was supremely clean and tight bass.
A good read on Holo Audio Spring DAC :
Holo Audio - Spring DAC - Level 3 - "Kitsune Tuned Edition" - Impressions & Reviews | Super Best Audio Friends