How about Brady crying to the referee during the Ravens game last year when he was barely even grazed...even more pathetic, the ref threw the flag. Funny, but they created a ridiculous rule that a defensive player on the ground can't reach out and tackle the QB; because of the Brady incident. So I'd say the NFL is more tailor-made for Brady. Has Manning ever had a rule created for him?
And this isn't even mentioning the tuck rule.
The organizational philosophy of every team has had to change because of Peyton Manning. The entire philosophy of the league was changed because they wanted to "re-emphasize" illegal contact rule. Peyton Manning is the reason the league is such a pass happy league. So I'd say the NFL is more tailor-made for Manning.