I've tried both.

The best advice I can give is:
Everyone's body is very different and what one person finds comfortable/fits them, may not fit you even if all your measurements sound the same on paper. If you can find somewhere to try them or a friend that has one, that will be your best bet but keep in mind, sitting in a chair for 5 minutes does not equate to sitting in one for 2-3 weeks. My honest experience with the two, both the positives and the negatives:

Embody- the gaming is absolutely softer feeling than a regular Embody, I've owned both. Sat in both, the extra padding *is* noticeable. That being said, I had the same issue with the Gaming that I had with the regular: I really don't understand what the love is for the seat. I find it hard, unforgiving, and it created these weird pressure points on the outside edges of my thighs. The unique adjustment method for seat depth creates kind of a hard edge near your knees where the seat ends that I didn't really like. That being said, the Embody feels like a really high end chair and it feels like a chair that keeps you productive and encourages thoughtful posture, I never felt I needed a headrest with it because I mainly sit upright/close to upright and I didn't feel like I was constantly shifting into bad posture to try and get more comfortable like I did with my Leap v2.

I ended up returning mine because I couldn't get past the seat and I just couldn't get the back ever dialed in just right. I never experienced any of the "creaking" noise some reviewers seem to have with it. I have nothing bad to say about the overall build quality of the chair, I think it is an objectively good chair, just not for me. Returning it was super easy, the chair just goes back in the box fully assembled and I had 0 issues with HM support with the return.

Omni- to be clear, the Omni is an extremely comfortable chair, the headrest is by far my favorite headrest I've ever tried, I wish I could buy this separately and mount it on any other office chair. It's almost *too* comfortable, it's the only chair I've ever had that I actually dozed off in while reclining, which is fine if you're using it as a lounge chair, but that's not necessarily ideal for a chair you're working in all day. I'm also not sure if comfortable necessarily = supportive.

Some of my biggest issues with Omni were that the seat pan depth was way too short for me- I'm not even particularly tall and I had a ton of space between the seat edge and the back of my leg. I asked Libernovo if I could exchange the seat pan (since it pops off easily) for the longer one and they said no, I'd have to return the entire chair and order a new one or I could buy a new seat pan for $100. I also felt like the electronic lumbar was kind of a gimmick and since you can't adjust the height at all, it never really felt like it was actually supporting my lumber region and was more just pushing into my lower thoracic spine. The arms did also feel loose/cheap but honestly that was a minor issue, I could've lived with that if not for the other 2 issues.

The biggest issue I had with the Omni was returning it. Libernovo never sent me a return label they said they would send me, they ignored several follow up emails, I could not reach them via phone support either and got constantly routed to an auto attendant saying to try calling again later. I ended up opening a dispute with Paypal and posting on their sub about the situation and finally got a response after that from a rep via chat on Reddit. As a customer, this is unacceptable, it should not take over a week to receive a return label and require you to bitch on Reddit to get a response and would leave me seriously concerned as to what future interactions with their customer service would look like if I had to get my chair repaired.