There is a Corvette that comes to the local car meet every year - black plastic dip. He says he has to resparay EVERY year to maintain it.
As far as I can tell, it's not a permanent solution, and will not hold up over time.
I used it on my Volvo bumper, precisely becuase it can be peeled off in sections. I wanted to play with a variety of reversible mods. As Jeff pointed out, it's typically used as a temporary cover over already good paint. Seems extragant to me to do an entire car only to peel it after a few months, but there are many people who do just that...