Tepper crawfishes a bit at the end, probably to spare himself the wrath of Manzielians on twitter, but I'd say the statistics clearly favor Griffin against the top 5 defenses each team faced. He averaged nearly double the touchdowns and exactly 100 total yards per game more. Their overall statistics are close, sure, but Griffin also faced better defenses overall (GASP!!! yes, it's true). In fairness, Manziel is two years younger.