I did the lower beltline on my Jeep Liberty when I had it. The bumpers/flares and plastic "Sport" trim were fading so I sprayed them along with the lower doors black. I just used rattle can and it came out good and held up well. It was rubbery/tacky at first, but I threw some cheap Turtle Wax spray wax on it, and it make it non-tacky.
I also painted my wheels on that with the DipYourCar anthracite in spray cans, along with their glossifier. Again, held up well enough on a DD - I drove it for about a year with the dip on, and no issues. Sold it with it on.
Overall, for the cost and ease of application, I was satisfied with it.