I have these in all my vehicles and have never had a problem with them
Seriously, I bought one for $40 off Ebay, mounted the camera on the back of my 26' RV trailer, wired the cameras power supply into the trailers tail lights and when I want to see whats behind the trailer, hitting the lights on the truck turns the camera on and the screen on my truck dash shows me everything I need. The camera must be over 40' from the monitor an it works just fine
I would say pick one with the size screen you want and go for it. If the cheapo I bought works I doubt there are many bad choices.