No tunneling that I can see.
Yes, the turrets lock by pushing down (much like a Vortex Gen II Razor).
No, the illumination dial is fairly unobtrusive; again similar to Vortex and Burris.
Blows a Khales out of the water (as well as S&B, Vortex Razor/AMG and Nightforce). Tangent Theta might be a hair more crisp in the "pop" factor, but not $1000 more "pop" (honestly, they're so close it's really personal preference). Khales always had that CA fringe that drove me nuts (kinda like the Burris glass), especially in snow covered terrain (like the Nebraska Big Horn Steel match I shot a little over two years ago; where my avatar photo was shot).
ZCO is definitely a Tier 1 scope...and the MPCT 3 reticle is very well thought out. It's there with all it's ticks and measuring devices, but somehow seems uncluttered. Probably largely due to the 0-2 Mil hold overs being minimal (no line, and just full Mil circles). I like the circle whole Mil marks; makes it easy to hold onto the target, without obscuring it. A shooter definitely designed the reticle.