I've used several night vision scopes and goggle sets...also thermal imaging systems.
The first I used was a Gen 2 night sight... I was quite impressed initally with the "new" capabilities but soon learned there seemed to be a trade-off. If I hunted in an area unfamiliar to me I couldn't judge the distance to the critter (monocular system) very effectively... Hell.. I snuck/sneaked/krept (??) up on a few deer to within 10's of yards without realizing how close I actually was... Another problem I had was without depth perception I had trouble walking around sometimes (no alcohol involved), used the big "foot stomp/poke" method of testing for the ground at times. These depth perception problems exist for me no matter the Gen NVG or thermal system.
Another thing that seems to be a little problem for me (and others)... deer are hard to see when using night vision no matter the Gen (thermal's a different matter entirely). They seem to possess the ability to "disappear" into the background... I suspect something to do with their fur. I found that I could often easily identify them by looking for their shadow and would position myself so that the moon or starlight would be greatest beyond the deer and I'd see the shadow(y) side as a darker image on the light background. About the furthest I could use the NVG Gen 3 was 400 to 450 yards... couldn't see critters any further.
Thermal.... aahhhhh, very nice stuff, a little pricey though. (the unit I borrowed/tested was in the USD $45,000.00 range). Many options, preset reticles, on-off switches and sensors, camera adapter, yada, yada, yada... I could easily see deer to well over a mile and there's little else that can hide from this system (unless specific attempts to defeat the thermal system are employed by the observed).
I like NVG systems, they're fun and have a use but they have limitations (IMHO)...
Note that on the NVG systems I did not use an illuminator for the Gen 3 model as it could see further than the illuminator would project under normal clear sky operation.
