I rolled white Rustoleum Industrial on my Valiant in early '06. The car has not spent a night (or day, for that matter) in the garage since. It has been through a Texas summer, several West Texas sandstorms, snow, rain, high-speed bug impacts, some neglect, the Walmart parking lot, and a lot of driving.
It still shines, at least when I knock the dust off. It has a little parking-lot rash, but no worse than any other car that regularly goes to work or the store. No peeling, no fading that I can tell.
I'm happy with it.