The new styles are much better than the ones from just a couple years ago. I watched a guy trying to set one up a couple years ago at an RV show, and he was at it for about 15 minutes and still had a few minutes to go. All the rails had to be mounted and it looked like a real PIA. The new styles are much more convenient since the rails stay on the door and just fold down.
I don't have or want one but have watched the evolution of them.