I used a stone guard in my tray before painting it the same colour as the ute. Takes the focus off all the dents and stuff but you can still see them. If I was doing a show car not a work ute, I probably would have spent the time to fix the dents or lined it with a wooden floor.
In short - stone guard is a good cheap, take the focus away thing but for anything that you really want to look good, forget it.