Testing now, here's my observations (no EQ/filters involved here):
1. On IEMs - in my case, IE900 - the difference between Hugo 2 and Mojo 2 is rather subtle. Hugo 2 has better micro-detail, better layering, better imaging, but the difference on a technical level is notably closer than between Hugo 2 and Mojo OG. Hugo 2 hits harder - has better dynamics - than Mojo 2, and generally has more of an authoritative feel.
2. Bigger differences come into play with full-size headphones that are moderately hard to drive. On the ZMF VC, there's no doubt that the Mojo 2 can drive with some headroom to spare. But the Hugo 2 offers a more defined presentation, with a greater sense of space. Mojo 2 has a sight "softness" in comparison, where separation especially isn't as precise (though I have to say again, it's a marked improvement on Mojo OG). I'm also comparing this on my TT2, incidentally, and as you might expect - there's a continuity with Hugo 2 and Mojo 2, but TT2 offers a level of micro-detail and clarity that is lacking on the others.
3. In terms of timbre/tonality, this was interesting. With the VC, my preferred source is Hugo 2 by far. The Hugo 2 has a super clean presentation which works especially well with warmer headphones, I find. The Mojo 2's timbre is close to Hugo 2, but it's nowhere as forward as Hugo 2. Mojo 2 has a slightly smoother/rounder top-end, whereas Hugo 2 is ultra-energetic in comparison. I'm a big fan of pairing Hugo 2 with tube amps; this is where the Hugo 2's magic really comes to the foreground, IMO. Some will likely prefer Mojo 2's slightly more cohesive timbre, I expect. The TT2 tonality is interesting - it has more body than Mojo 2 and Hugo 2. The overall presentation is more refined, more subtle than Hugo 2. On brighter headphones - Kennerton Rognir/HD800s - the TT2 is by far the "winner" in terms of synergy. The lower end body gives a tremendous sense of body that is not as evident in Hugo 2 or Mojo 2.
In sum: Mojo 2, Hugo 2, and TT2 are - IMO - mutually edifying and complementary. And, of course, they each serve a different function. They share the same Chord signature, but present in different ways and with varying levels of technical excellence. Placing the Mojo 2 against even the TT2, it's impressive how well the former fairs. I remember doing multiple tests with Mojo OG, and it felt like a huge step downward switching between TT2/Hugo 2 to Mojo OG. The Mojo 2 holds its ground with ease. It's an amazing achievement.