I don't have a back up camera but I assure you, I would use it if I had it!
Right now I do the looksee technique. Back straight up, get out and looksee, adjust as needed. It was REALLY aggravating at first but now I am pretty decent at it. Usually its about 2-3 trips out of the truck to the back to get it right. I have only hit my license plate once in 3 years. LOL
I have seriously thought about adding a monitor in my cab and installing some sort of camera to keep an eye on the hitch while pulling. Sort of a permanent back up camera system.
Thanks!
Jeremiah