The irony is that some of the Peyton's best games ever have been in the playoffs - torching the Broncos number 4 ranked D following the '03 and '04 seasons, torching the Jets number 1 ranked defense in the '09 AFCCG, lat year's gem in the AFCCG, etc. - but all some want to remember are the losses. It's just the way some are wired to think, I suppose. I think what hurts the perception of him the most is that he hasn't played all-time great in any of the Super Bowls he has been in. Even though he was the MVP of the win over the Bears, his stats weren't gaudy, in large part because that game was played in a rainstorm. Last year hurt the perception, but history is already showing that that Seattle D is one of the best ever, and Joe Montana on his best day would have struggled with the way that defense was playing that day. But all seem see is, "Peyton lost," and resort to the silly "Peyton is a choker" narrative. Yay for the internet and brain dead opinions though.
Bottom line for me: both Brady and Peyton are in the top tier of all-time great quarterbacks. Who is better? A very strong case can be made for either. I think most objective people would agree with that.
The other interesting thing is that, for the last decade, Brady has basically been everything that people bashed Peyton for, but they refuse to criticize him for the same.
Gaudy regular season stats, duds in big playoff games and at the ends of games. He took a 17-0 team with the best offense in history and put up 14 points in the Super Bowl. Late interceptions in big games, including one of the Super Bowl losses. A QB rating under 50 in the 4th quarter of AFCG/Super Bowls. And the last few years, among the league's worst in percentage of game winning/tying drives converted.
Yet, like you mentioned above, all bad things swept aside because of a few games he played really well in TEN YEARS ago.
Once people have made up their minds, anything that doesn't jive with it is ignored for all eternity. Tony Romo can throw for 400 yards and 3 touchdowns this week but anything less than a Super Bowl MVP means he's a choker. Meanwhile guys like Brady and Roethlisberger can go one and done as many years in a row as they want and no one will ever think any less of them. Minds are already made up.
I think most would agree that Tom Brady of the last 10 years is a much better QB than the game manager Tom Brady that won 3 Super Bowls with good defenses early in his career. But Tom Brady of the last 10 years IS Peyton Manning, with one less Super Bowl and slightly worse playoff stats.