RE: Leupold or Zeiss ?
Both are good. I picked the Zeiss over the VXIII, just seemed to be the better optically to my eye. So far they have been great, so no complaints.
Yes the zplex is a duplex reticle but much bolder than the regular duplex the VXIII uses. It is one thing I really noticed and prefer when comparing, seems to jump out to my eye. Works great for low light. I have grown very fond of it and hasn't caused me any concerns in regards to shooting distance.