I put steel tie downs on my truck. Up here where they put more salt on the roads to de-ice than a fast food restaurant puts on their fries, it doesn't matter. Steel rusts, aluminum oxidizes when they get in combination with winter road slop. I don't drive the truck much in the winter, but they are already showing signs of rusting after 3 winters, plus driving gravel roads in the far north where they use salt to control dust.
My truck is black, my camper white and my Fastguns are Stainless. Doesn't look too bad, especially when they get covered in dead bugs. They get washed off and a little scrubbing doesn't affect the stainless.
Brian