I tried the Blackvue 2 Camera system and while it took decent videos, you always had to be near Wifi with the camera and be connected to Wifi just to find your videos on the app and download them. That was just to get them from the camera to the SD card.
There really wasn't anywhere for me to place the rear-facing camera and the double-sided tape wasn't all that great for the roll bar, so I had zip-tied it. Eventually the rear camera quit working after a 4-5 months. Finally, the front-facing camera fell off of the front windshield. I just never bothered to put it back.
I had a basic Rexing camera for a while before I had my JK and it was ok, it just randomly quit on me one day after about 8 months.
I plan on doing more research on cameras before buying another one.