Ya know, I'm thinking I *want* stuff to slide in the bed. There are not many times I don't want it to be just about like a steel truck bed, lol.
Except when something slides out of the truck, or when your foot goes out from under you and you fall. I recall using my dad's maroon 96 f150 that had a rigid plastic Bed liner for hauling dirt. It was super easy to sweep all of it out, it had the channels that ran the length of the bed. Try that on my factory spray in liner and I guarantee it would not sweep out easily due to the grippy surface. Again, pros and cons to each.
Have a slide in bed liner in my 1990 Ford Ranger. It is slippery but I do not have to worry about the bed when throwing logs or wood in. The bed itself is a mess since it is now all rusted. Without the bed liner I guess it would be rusted and dented. Slippery can be good or bad. When I have a load of wood I can just lower the tailgate, go in reverse, and hit the brakes - the truck empties. Best thing about the liner is it is guaranteed for life since I bought it from Ford when I bought the truck so when the truck rusts out and dies I will still have a bedliner.