A couple of comments re the MK II:
I agree with Wildflower about the MK II stabilizing after warm up. I would also mention that even if I've let my cold MK II go for too long without a nuc, the image has never degraded to the point that I couldn't take a quick shot at an opportunity that pops up, which happens when predator calling.
Nuc'ing the MK II once you are used to it is a quick and simple one hand operation that can be done without looking at or though the scope, and takes only a couple of seconds, nowhere near six seconds once the operator gets the process down. I'm lefty so the process for me is close the lens cap with my right hand's ring finger and pinky, rotate the top knob with my tumb, wait one and release the lens cover. I can do it on the move without fumbling.
I am now using Ultimate Night Vision's rechargeable remote battery pack, and leave the MK II on anytime I'm not in a truck, and battery life is no issue at all. Before going to the remote battery pack I only turned the MK II on when on a predator stand or when approaching hogs (because changing the MK II's batteries in the field is a little bit of a pita because of tight clearance between the battery compartment and the AR's receiver rail.) It takes no effort to nuc it a couple of times on approach. Perhaps the only issue is that when the MK II is turned on you need to switch menu pages to get to the page that operates the nuc, and it's a different page than the page that operates the zoom. I think IR would have done better to have the zoom and nuc operations on the "home" page which comes up when the unit is turned on, especially since the last brightness and contrast, etc, settings are remembered when the scope is rebooted.
On the Zeus 3x 75mm vs. the 35mm MK II, I had the opportunity to compare them in about the worst conceivable thermal conditions and I thought there was no appreciable difference in performance. The fellow who owned the Zeuas and had the chance to compare it against my MK II thought the same thing.
On auto nuke, it's nice to have on a scanner, and it is nice to have when you loan gear to an inexperienced bud. But once you use your non- auto nuc gear a bit, the process just becomes, well, automatic... I have an HD 19A scanner with auto nuc, and after using it I would not want auto nuc on a scope, and, if the scope had it, I would turn it off.
Edit to add: On native magnification, so far, it seems that about 2-3x is the best compromise for a scope. Less is better for a scanner.
My thoughts, worth at least what you paid for them!
JPK