According to my own experience you should choose only reliable brands like this thermal scope www.atncorp.com/thermal-scope-thor-hd from ATN for instance. When choosing thermal optics, be sure to pay attention to indicators such as matrix resolution and frame refresh rate. The quality of the image at a certain distance, as well as the ability to constantly monitor prey, will depend on this. Hopw it will make sense for you
One is best in terms of resolution and accuracy. I dont really know which is best by that standpoint, since the high-resolution, high-accuracy thermal cameras are way, way out of my price range. I suppose you wouldnt go too far wrong with any of the higher-end cameras, like this one - FLIR T540 Professional Thermal Camera