I vote for Knapp.
I hated Punnett when he first started, but then I got used to him and even stood up for him when someone put him down because it seemed to me that he really did his homework and many times had even read the book that the guest is pushing.
I'm back to not liking Ian anymore, and don't listen to him. He stammers and stutters until I want to hit him in the mouth and he is UNfunny and tries too hard with his stupid "jokes".