This is the only kind of paint i use on chassis components simply because the semi-rough surface will hide imperfections and is easier to touch up.
Durability of a paint product has less to do with the paint and more to do with the prep. I like to hit stuff with a DA sander to give the paint some tooth, then hit it with some MEK or Mineral spirits to remove oil and dirt.
Paint goes on easy, covers up easy and can be cleared over. I've painted my axles, and frame modifications and they were also cleared and look great (minus abuse). I did also painted my rockers guards with this paint and did not clear over my them and after years of sitting in the sun, abuse, crappy re-paints, the paint still looked good.