Some ir are visible,the one i have on my Digex is invisible to man or beast.I really like thermals for target detection and NV for shooting. I run a handheld thermal for finding animals and then NV for confirming the animal is what I think and taking the shot. If your in an area that has fox, bobcats, the neighbors dog potentially running around thermal may not be clear enough to differentiate them from a coyote. Other upside to Night vision is you can see IR lasers, you can't with thermal. I have a weapon mounted rangefinder and can see the laser through my night vision on my target to ensure I've got the correct range for long shots on 'yotes at night. The new FLIR IR Hunter has me considering another purchase and going to a thermal over night vision but I'm still not sure because of the reasons I stated above. Ultimate Nightvision offers rentals on some different systems so you could try them out and the rental price goes towards your purchase if you then decide to buy one.