I just sold my Hellion V2 after 1.5 years of owning it. I got the MOAB+ and after a few weeks sold the Hellion. That's not to say the Hellion isn't an absolutely fantastic, first rate fucking amp. Its the longest I've owned any amp. But while similar in some ways, they are very different. Similar in that both can be open and raw or compressed with gobs of gain and compression, both have great clarity/definition/articulation, both are very fast in the attack, aggressive as hell, and have little to no sag.
The MOAB+ is Marshall true and true in voicing while the Hellion is a Hellion in its voicing. If I had to put it in a box, which I hesitate to do because it is it's own thing, I'd say its like a mix of a Mark series and a Marshall kind of. The Hellion is a more modern sounding amp because, well...its a modern amp with modern components. The MOAB+ is your donor components with some modernization, so it retains a lot of that vintage raw/warmish yet aggressive nature. Ultimately I found the MOAB+ capable of more open/organic tones and feel under the fingers, punchier, wider sounding, and more articulate. My guess is the Dagnall or Drake iron plays a big part. I've not played an amp like the MOAB+, it leaves my jaw on the floor every time I plug in. Even next to the Wizard Hybrid I recently grabbed to direct compare, and I absolutely adore Wizards, but if only one amp could stay, it would be the MOAB+.
It sucks bigtime I sold the Hellion, I love that amp and I think its one of the very best made modern amps today. Wish I could keep them all, but its a give and take game and part of the deal for me in this hobby.
I'll add that I also have a GZ Trem Recto and its also among my favorite amps...top 5 category.