The Mojo cannot be separate as a dac or amp second, so I am only commenting on the Mojo vs the x7 separately. For my ears, I am really impressed how much the x7 and Mojo sound alike. I do not hear the x7 as warmer than the Mojo, at least it is not obvious enough for me to pick up. They both seem very close to balanced and natural to me, nothing emphasized on either for me. The x7 has a bigger soundstage, the Mojo is a little more dynamic to me. I would say they both have an equal level of resolution and extension with detail on either end. Honestly, the soundstage is what stick out to me as the only significant difference, and the Mojo soundstage is just fine for me, the x7 is like a bonus that way. The Mojo is a bit easier to engage with atower levels, which is why I think it has better dynamic range.
I use the x7 for iems on the go, we then hook it up to the Mojo at home for my planars. I am very happy with this setup. Can't go wrong with either unit imo.
Edit: forgot to add that I find the e12 and c5 amps to have less resolution and a bit of colour added to the music (warmth added with e12, brightness with c5) . They just are not as detailed to me. Ymmv of course, maybe I am just justifying my own purchases subconsciously lol..