Just an initial impression, not yet burned in, but Mimby is as good as they say it is, for me in my set up.
Neutral, with just a touch of upper mid emphasis, giving great imaging, and the soundstage, while not huge, is reasonably wide and high. Bass is realistic, not bloated or forced, allowing the music to flow easily, without Mimby ever intruding.
Overall, sounds very musical and engaging, with very good pace and rhythm. Clean, clear and sweet with HD600, DT880 and K712. Tested with Elise 6 pack, and Espressivo, EL3N powers, Mullard ECC88 Drivers. I also connected the headphones directly to the outputs of Mimby, without using an amplifier, with similar results, amplifier just goes louder, of course.
Mojo sounds almost identical, strangely enough- maybe not quite the inner detail, but perhaps a bit more depth to the sound. Both excellent with neither sounding digitally 'processed'.
Mojo is more expensive, but you do get a good headphone amp ( two outputs, actually) and it's transportable, being battery powered. Both great value depending on whether you want just a DAC or a DAC/Amp.
Thanks for your patience, DL, I'll be interested in your own assessment, though I don't know that other amp you're comparing with.