I have one camera mounted on the headache rack of the FL that I use to help connect to the trailer. I really like the camera assist for hooking up, other than that, IMHO, they are just a distraction. If I am concerned about backing into a space or whatever, I just would not trust the view of a camera. I find that in watching the camera, you tend to focus on that and your eyes are not moving to check mirrors, etc. For us it just works much better to have my wife standing either in fron or at the rear of the rig. For the rare times that I have had to manuever the trailer when alone, I have always been able to find someone to assist.
Tried the camera route with our previous tow set up and really did not use it. One thing I have used is the driveway marker poles with the reflectors that you can purchase at the Big Box stores. I used to set one of those out for a reference point when I had to back the trailer into our storage facility, and found that to work really well. Just my opinions based on my experiences and preferences
Whatever ever you use....get out of your rig and check everything before backing.....go slow....don't be afraid to stop and get out to check!
Travel Safe!