Really. I would say, that without a doubt it is Peyton Manning. Next would be Brady, then Favre, McNabb, or someone else. People say Manning can't be Belichick, but here's my question, could Brady beat Belichick if they were on opposite teams? No.
I think that is a question no one can answer. I would say Brady/Manning comparison is equal to Montana/Marino comparison. One had the rings the other had the stats. I will say Brady has ice in his veins. The guy never folds under pressure. Manning has made some bad decisions in big playoff games.