I really like my "Ford Logo" drop-in liner. Installation is nearly foolproof. The molded-in ridges are high, for water run-off, so cardboard boxes/suitcases in the bed seem to stay dryer than with the steel bed. The built-in non-slip texture is effective, the price is reasonable, it's easily replaced when it's time for an overhaul, and as pointed out earlier: no dents in the bed unless you really clobber it. The molded-in platforms for lumber "shelves" and dividers are handy to help customize the load. All-in-all, a drop in is a pretty good solution to bed protection. The only drawback, IMO, is that any corrosion and rust problems under the liner can remain hidden. Good luck.
Larry in SF, CA