The D400, IMO, and I've owned a few, was the best breathing regulator I've ever used and to me by a noticeable margin. This new Atomic looks to be very similar to the D400. That being the case it should be a very very nice breather. I'd love to try one just to see.
The only thing that eventually turned me from the original D400 was inability to get new orifices, well any parts really, and it was tricky to service and a wee bit finicky.
If Atomic have addressed those issues I'd like one but I too will have to wait some years, win lotto or find an estate sale.
And no, I'm not saying it's going to change the world, I'm not saying Atomic is the best, I'm not buying Atomics advertising blurb, I'm not saying it's worth it's asking price, I don't have shares in Atomic, I'm not making any analogies, I'm not trying to convince anyone to buy one, I just think it could well be a very nice breathing second stage.