I've personally used the Trijicon M250, M300W, NVision Nox, AGM stingIR, Iray MH25 with the FLCOS, and the newer MH25 with the OLED, one of the only FLIR Breach 640 12 BOSON, and the Iray RH25 and RH25 V2.
I've used them as hand held, helmet mounted, weapon sighted, as well as clip on "if...