I've used them on and off for the last decade...
Trail cams are one item in which there is a definite price point you want to be over. You can get cheapo $50 trail cams. My Dad has bought be some for gifts, trying to be thoughtful. Most have sucked terribly. Low battery life and a very very slow trigger response time mean you get almost no useable pics.. These were budget Tascos and Bushnells. After playing extensively with these for an entire season, I finally gave up and tossed both in the trash.
I've bought a Moultrie and a Wild Game Innovations model. I cannot remember which specific ones. In both cases they were $110-125 units. They take decent pics.
Some units have various 'black flash' nighttime illumination. These are not visible. If they do not have some form of black flash, there will be a low level reddish glow from the unit when triggered at night. Humans will know, and will likely remove the unit if its being used for security.
Fro