The new
Diamond Shield Nano is a much improved product over what they had prior to 2011 or 2012. Tiffin had to replace the sidewalls on my coach so I elected to go with a different color arrangement, which of course meant repainting the front and rear caps. I had the Nano version installed and it's like another layer of clear coat.
I have friends that have removed their 3M or older Diamond Shield and now have a lot of chips and dings in their paint.
Like Don said, if you take care of it properly it will hold up fine.