I used Rustoleum on mine and have to agree I was worried about the durability.
In the two years of working on the truck I am suprized at how good it has held up to being used as a workbench, having the cab dragged back on over it, having parts bolted and unbolted, then bolted again. Very little damage is noticable. Much tougher than I thought rustoleum would be. Of course this will be a Sunday driver and won't see much bad weather.