Bicycles also have some plastic cards as well. Broken in paper Bicycle decks are fantastic, but very easily wear down and become marked when quickly shuffling and dealing. I keep them for Go Fish, not any serious game.
Paper cards are done after one five hour tour of duty. When you are running multiple tables like many here do, paper ends up being more expensive than a quality plastic deck which can last multiple games.
None of the above. Paper cards are very stiff until you break them in, then they play quite well but that doesn't last too long because they go limp pretty quickly.
Copags are plastic but garbage. With every shuffle they loose a little ink. After a few months of use they look like crap.