probably the 80/5 guy because from what you describe he is really exploitable post flop too. the other guy should be easy to make money off too but playing 80/5 and then folding when he doesnt having anything is just going to be exploited almost every hand.

edit: also the 80/5 isnt playing good postflop hes just not making huge spew plays. the 21/14 guy who stacks off too easy is still probably doing a lot of things good postflop and actually being aggressive postflop.