The Bering Optics - C clip on is decent but it adds a lot of extra weight as well as cost. Night Goggles sells the stand alone versions 100 to 1 in comparison to the clip on. The Clip On can be used a scanner, but you have to thread on an adapter eye piece and the eye piece modifies the image to 3x. This is probably OK for hogs, but is can be too small of a FOV for others. With the standalone Hogster R 25, 35, and Super Hogster, you can be just as mobile with the QR/QD mounts, less expensive, lighter, and not have to thread on an adapter to be used a scanner.
If you want a clip on, the Bering Hogster - C is nice, and I am currently testing their 640 version clip on and it will be nice as well, but I personally prefer the -R versions. I will PM my cell if you want to chat about thermals.