Fuck, I like them both.
The ZCO immediately makes sense to my brain and having 3mils up top (and only 3mils) seems useful. The hash marks are kind of dazzling to my eyes though versus the "visually softer" (if that's even a thing) JTAC reticle's stark minimalism.
IMHO I feel like the JTAC reticle's purpose is to not distract you after you break the shot so you can more easily pick up the impact/splash... and I like that... but it seems like it might be a little too thin for those of us who never dial wind (and my mid-40s eyes). But that could just be because I'm not used to it... having the least amount of "screen door" effect possible does seem like a cool proposition, I kind of have to see it for myself in person.
The ZCO looks sick, is slightly cheaper, and 15mils per rev fucks with my head, so I'm leaning that way. Though, now I'm wondering if it isn't as uncluttered as it could be, or maybe as sophisticated as the JTAC reticle?
Hopefully, I can see one or preferably both in the wild...