I had a friend in our club buy one. We spent several trips (on shot deer) trying to use it and never got anything worth paying for it. Thing is, I work for a power company and the electrical engineers I work with use a highly sensitive infrared camera to find hotspots on troubled power lines. The camera is $80,000 bucks!! That is just for the camera body. The lens is another $30,000 bucks!
I talked to one of the engineers about the camera and he told me in order to “see” differences in just one degree at a distance of 15 feet you would have to have such a camera to detect the difference.
So, I would say the bottom line is the game tracker concept is total bunk unless you have a 100 grand burning a hole in your pocket.
I would save the money and get a good Coleman lantern and a bright flashlight. I have trailed and found many a deer with a good old Coleman lantern.