I only know of them both from interviews on the various Marvel movie DVD's features, I mean it's not like they're constantly in the spotlight like celebrities on TMZ are that I can formulate an opinion on them.
Jeph Loeb is just some bald guy and Avi Arad from his interviews seems rather pompous when praising even the dumbest of Marvel movies as if he had a hand in creating them.
Avi haters are funny.The man is one of the main reasons why we even had Marvel shows in the 90s.
I know for sure that the head of Fox Kids, Margaret Loesch was ultimately fed up w/ having to do business w/ Arad, which in return, was one of the main factors behind the cancellation of said Spider-Man show.