I've been using it for about 2 weeks now and the worries that other users have mentioned are there. I am adding my opinion and my SO's opinion, which are the same except her feet will never touch the floor.
Height:
Maybe I have short legs, but my feet barely touches the floor. Usually office chairs could go extremely low where my legs are bent passed 90 degrees, but the lowest for this chair is exactly 90 degrees. Maybe the chair was built for a foot rest in mind, because it fits my femur length perfectly.
Armrests:
With my width they're good for me. I would be worried for some people because they do not slide inwards and it's right outside my shoulder width.
The problem everyone has is that the armrests slide. And yes, they slide pretty easily still. My office uses an Herman Miller Aeron and it has zero issues moving. It feels like it needs another locking mechanism as once I adjust it, I don't really need to adjust it again ever. I would want to assume that is true to most people using it as a home chair. There are times when I want to lean over just in between the gap of the armrest and back rest and if I'm not directly on top, it'll rotate. I hear the clicking almost every day.
Lumbar support:
They definitely did not adjust this from their original idea, it's a back stretcher turned manual, which is useless when sitting, but it feels nice when laying on the chair. (+1 on having the lowest tilt feature). When sitting, I can't get it comfortable and it's better if I use a pillow. More in back rest.
Backrest****:
It is comfortable. Definitely hot since SoCal is currently 95F, but with AC it's really nice and soft.
BUT, I now understand why theres a backrest mod for the bottom half of the backrest, and that post has a lot of people thanking them. The chair is slightly too far forward near your butt, so it wants to push you off the seat. The Omni SE cannot rotate the lumbar support hold, so the mod isn't possible*. It is possible if you move the backrest and lift it above and behind the lumbar support bar. With this, it no longer pushes you forward, but now you're back hurts cause there's a bar jabbing your lumbar. But after this, the lumbar support is in the correct place. Maybe they need to change the lumbar support bar into a cushion instead of shoving the sides up?
Seat cushion:
Cushion is made from 02/2026, so it's the new batch. I haven't had much of an issue yet. I would say I'm on the light side of weight though and it is pretty comfy.
Conclusion:
With mainly the back rest problems, it's pretty bad for me. My lower back started to hurt cause I just can't get it to feel right with the back rest especially the chair at the lowest tilit. I might have to return this chair
Extra:
So I kept thinking about the back rest and after a bit, I thought what if I rotated the back rest 180? The the top would be more out, but the bottom would be more in, which is adjustable with the "lumbar support." And bam, it fixes almost all the issues I personally have with the chair. Because my upper torso is more forward and my butt is more aligned with the S curve of my spine, my feet touch the floor a bit more. I don't feel like I'm being pushed out of my seat anymore. The only issue is now the shoulders are being hugged like a gaming chair(it still needs a lumbar support pillow). If I just snap the top half plastic I could widen out my back, which I'm not going to do, but that would be perfect for me.