Judging the better quarterback career

On the eve of the AFC Championship Game, many people are considering Peyton Manning's and Tom Brady's so-called legacies. Who had the better career?

I think the most obvious comparison to their rivalry is Dan Marino and John Elway's. Until very late in their careers, it was a debate. Then John Elway pulled ahead, and is by consensus considered Top 5 all-time. Marino's no longer in that discussion.

Why? I looked at several relevant numbers that quarterbacks are judged on. I'll first look at Marino and Elway's career, and put in bold the stat in which either had a clear advantage.  

Marino:

Total years as starter in majority of games: 16
Winning seasons as starter: 10
Super Bowl record: 0-1
Playoff record:  8-10
Yards per game, passing: 253.6
Passer Rating:  86.4
MVPs: 1
Pro Bowls: 9
First Team All-Pro: 3

John Elway:

Total years as starter in majority of games: 16
Winning seasons as starter: 12
Super Bowl record: 2-3
Playoff record: 14-7
Yards per game, passing:220.0
Passer Rating:  79.9
MVPs: 1
Pro Bowls: 9
First Team All-Pro: 0

Elway's Super Bowl runs late in his career, and total number of Super Bowl appearances, but him at a clear edge, even though he was never a First-Team All Pro. Why is he now considered the greater?

It comes down to:

More Super Bowl Appearances: 5 to 1 (+4)
Super Bowl wins: 2 to 0 (+2) 

Now, let's compare Brady and Manning, admitting Manning has some greater stats due to playing three years longer:
  
Peyton Manning


Total years as starter in majority of games: 15
Winning seasons as starter: 13
Super Bowl record: 1-1
Playoff record:10-12 (as of January 18, 2013)
Yards per game, passing: 270.7
Passer Rating:  97.2 (though just a slight edge)
MVPs: 5 (*assuming he wins in 2013)
Pro Bowls: 13
First Team All-Pro: 7

Tom Brady:


Total years as starter in majority of games: 12
Winning seasons as starter: 12 (ever season)
Super Bowl record: 3-2
Playoff record:  18-7 (As of January 18, 2013)
Yards per game, passing: 254.7
Passer Rating:  95.7
MVPs: 2
Pro Bowls: 9
First Team All-Pro: 2
 
If Brady wins tomorrow, he'll have a +4 edge in Super Bowl appearances, and if the Pats win the Super Bowl he'd extend his lead in victories to 3 (4-1). Even if they don't win, Brady would have the same margin over Manning that Elway has over Marino.

At the same time, Manning doesn't need to catch up to Brady entirely to perhaps surpass him in the all-time rankings. By winning tomorrow, he'd be -2 in Super Bowl appearances, and if the Broncos win will move up to -1 in wins.

That would be close enough for Manning to be considered the best qb of the era. After all, championships aren't everything in measuring players, including quarterbacks. Terry Bradshaw isn't mentioned in the same breath as Joe Montana, even though they're both 4-0 in Super Bowls. Troy Aikman isn't considered better than Steve Young, even with two more Super Bowl victories. The overall career counts as well, and Manning would silence the debate between him and Brady with another Super Bowl victory.

And if he doesn't, and at three years younger, Brady would make a pretty compelling case himself.