I have an armasight spark CORE unit, and I'd have to say, from what I've seen, it's the best cheap unit going, at around $500+.
It's technically gen 1, but the tube is made from a different kind of glass. It has the resolution and clarity of gen 2, but light amplification of gen 1. I've had it see nothing out in the sticks on a cloudy moonless night.

The only problem with flir type units is that, unless you go high end (like NV), it can be difficult to use for just moving about. They don't "see" like vision does. Great for hunting something, though.

Ideally, you have both.

I still have the first cheap gen 1 monocular unit I bought (about $350), the armasight spark monocular (about $500), and a set of modular goggles, gen 3 omni III autogated, Socom grade tubes.
Those things are unbelievable.

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