A few observations:
1) This spring was very wet and humid. I discovered that the IRD always worked much better than the Armasight in those conditions.
2) The Armasight Zeus 640 3-24x75 (60Hz) is actually 2.7X mag instead of 3X. Read the fine print, we have NTSC systems here.
3) The auto-cal waits too long between NUCS, so you end up manually NUCing the scope anyway. Advantage over IRD gone.
4) The video out is always on and I like that. Just wish they didn't port it out of the scope vertically. You have to be real careful with your cable.
5) The buttons for operating the scope are small and recessed. It is a pain to get your fingers in there.
IR Defense for me all day long.