Hi Dick & Mary,
I had one on the Excursion a couple years ago. I just never liked the idea of it in the first place, and wasn't a fan of the screen sticking up on the dash (I've never been a fan of window mount GPS holders either). It worked pretty well during the time it was on, but I did make one mistake. Naturally, from driving on wet roads, the end of the camera got wet. I tried to put RainX on it, and it scratched the lens so that it was difficult to get a clear picture on the screen inside.
I thought about putting it on the back of the Sunline, but since it needs a backup wire feed, which isn't back there easily, I decided against it.
We have one on the pickup from the factory and I love it. Unlike the aftermarket one, this displays in the rear view mirror, and the best part I like about it is the center line it puts in the screen. I am able to hook up a trailer by myself without getting out. I got to the point where I can do it with the Excursion using the mirrors and backup sensors, but the camera is much more accurate. The one downside I've found is that since it is mounted in the tailgate handle, depth perception is skewed and I end up not being as far back as I think I am when looking at the coupler. I suppose over time if I did it regularly, I'd get used to it quick. So I'd look to see if any aftermarket ones have a center line display, I think it would help a lot.
Jon