For hauling a camper I can't imagine a drop in liner is preferred for any reason.
Bare steel bed and a rubber bed mat works great though.
I'd never put a plastic bedliner in......unless I had a really nice truck and was abusing the inside of the bed, like hauling junk, heavy construction or tossing log rounds in load after load. Plastic bedliners absolutely protect the bed from impacts/dents the best by a long shot. Other than that, not a fan.
As far as rubbing paint off, that's a minor concern IMO. Any beds that "rust out" from a drop in liner, well, the rest of the truck is 99% guaranteed to be rusted out too.
