Playoff performances? Brady's last4 or 5 playoff games have been abysmal.
And you spelled intangibles wrong. It's spelled D-E-F-E-N-C-E.
Brady has struggled in a few playoff games, but abysmal is a bit of an exaggeration. The Ravens game last season and Chargers game in 2007 were pretty bad, no doubt. But the Giants game, despite the outcome, was pretty solid especially considering how much pressure he was under. The Jaguars game was a record-setting performance. And the 2006 AFCCG loss to the Colts was a pretty good performance as well, as he actually had a higher passer rating than Manning.
Regarding intangibles, just want to add you won't hear Brady claim after a play-off loss that, "I am going to try to be a good team mate here, but we had our protection problems."
As for defense, the Patriots have been better statistically, but the Colts have been much better offensively. They're totally different teams with totally different styles that help account for the differences in both areas. As an example, the two teams played very different styles early on. The Colts play a lot more no-huddle, while the Patriots, especially early in Brady's career, focused on ball control and clock killing. Home environments and weather make it a difficult comparison as well.
But since 2001, the Colts have won 105 regular season games, the Pats 107, so you can't really say either formula wasn't as effective as the other. During that time, Brady went 14-4 in the play-offs, and only once was he one and done (last season). Manning went 9-9, which would be much worse if the defense didn't carry him to 4 straight wins in 2006, and went one and done 6 times.
Manning is a great QB and I understand the arguments for him being the GOAT. I'd still rather have Brady though.