They perform very well for the price range they are in. I have looked through a lot of thermal optics lately and these new boson cores make a huge difference in the appearance to the eye. I feel like it makes a 336 look just as good as a 640. The only negative is the field of view is smaller than the 640 units. But for identifying possible targets at a distance this can sometimes be a good thing. Donkeys around 80 yd, rabbit 25 yd. White hot obviously. Sorry don't have any longer range pics stored on this computer.