I'm a big fan of the Sig Echo3, but there are downsides. Pros are good resolution, fast and accurate, great contrast and brightness, super light and compact, and, in my experience, a MUCH further effective range than advertised. I used to live beneath a mountain, about .5 mile from the base, and I could often catch glowing signatures walking all along the mountain at night, at what must have easily been over a mile. Con is an obnoxious click that happens every ten or so seconds. Not loud, but enough to make you wonder why it's there. Also uses the old USB-type charger, rather than the new universal one that everything has. The other con is kind of a pro. The screen is open, so it can easily be used a kind of thermal reflex sight. Would be great for self defense because you just throw it up and go, no cheekweld, no cup. BUT, this makes you kind of night blind during long hunts because it is impossible to keep both eyes from taking in some of the light.
As a side note, sig doesn't advertise that the Echo can use a backup battery, but it does charge from an anker (they confirmed over email, I never tried it because the battery by itself is pretty good). Don't buy it from a dealer. I've seen them sell on forums/ebay for much less than MSRP. Street price can be as low as 2k if you are patient.
