Right now he's probably not top 5 on most rankings.(http://www.autoadmit.com/thread.php?thread_id=5283013&forum_id=2#45879520)
I think 3 is solid (http://www.autoadmit.com/thread.php?thread_id=5283013&forum_id=2#45879524)
You can deduct points against Manning for being a contemporary of Brady and therefore not the best of his era.(http://www.autoadmit.com/thread.php?thread_id=5283013&forum_id=2#45879533)
aloso manning has had insane wepaons and oline unlike Marino who had maybe very few seasons without insane offense weapon or blockers or even rb
(http://www.autoadmit.com/thread.php?thread_id=5283013&forum_id=2#45879875)