Manning, without a doubt.

From career stats:

Yards/attempt: Manning- 7.7, Favre- 7.
TD:INT ratio: Manning - 2:1, Favre - 1.5:1
Sack rate: Manning: 3.3%, Favre, 4.8%
Fumble rate: Manning: .9%, Favre, 1.7%

In Favre's prime - 1992-1997, he averaged 6.3 to 7.7 yards/attempt.
In Manning's 1999 - present - already longer than Favre's best years, he averaged 7.1 to 9.2 yards/attempt

I could pull up more specific details, but they'll be pretty similar to the career numbers.

Pro bowls: Manning has missed the pro bowl twice. His Rookie year and 2001, totalling 9 appearances, 3 all pro, and 3 MVPs during the regular season.
Favre has had far more years to accumulate pro bowl appearances, but has "only" 10, with 3 all pro appearances.

You could harp on the Pro Bowl being a popularity contest, but the other statistics are more compelling to begin with.

I could go in to more details and more advanced statistical analysis, but while Favre was a great, and is a first ballot HOF player without the slightest doubt, Manning eclipses him across the board as a better QB.

NFL historical accumulation numbers:

Completions: Favre - 1st, Manning, 5th
Attempts: Favre - 1st, Manning, 8th (Note that the lower ranking in attempts than completions is an example of a higher completion percentage for Manning)
Yards - Favre - 1st, Manning - 7th (Manning still has higher yards/attempt than Favre does, but some other prolific QBs have slightly higher ones)
TDs - Favre - 1st, Manning - 4th (More TDs per pass for Manning)
Interceptions - Favre - 1st, Manning - 42nd (Well, this one speaks for itself)
Sacks - Favre - 5th, Manning, 76th (Manning is one DIFFICULT guy to sack!)

NFL historical best yards/attempt per pass:
Favre - 78th (tied with many)
Manning - 12th

Yards/completion -
Manning - 150th
Favre - 190th
Ah, yes, the days of the past when QBs completed far fewer passes for a couple yards/each more.



Neither Favre nor Manning transformed the way football was played like, say, Sid Luckman did. In a time where football QBs were horribly inefficient, Luckman transformed the nature of the game entirely, putting up numbers in 1943 in particular that looked nothing remotely like what anyone had ever accomplished before.

Brett Favre. He's still around, so we are able to compare Peyton Manning with Brett Favre in their primes. Brett Favre is a way better quarterback. His immense control and ability is unmatched by any quarterback. The fact that he's first in so many record and there is no obvious second place that matches him is a testament to his ability.

I'd take Manning. Not because of the excellent statistical analysis above, but Manning is a team leader, the kind of quarterback who will execute a system to perfection. Favre is a gunslinger. He can make things happen, good and bad. He will complete passes that nobody else should ever attempt. But he won't pull the team together, and he won't allow you to build and execute a complex system. If I want someone who will instantly add excitement, and may well win any particular game, it's Favre. But if I want to build around someone, and if I want to implement a system that builds on the strengths of all my players, I'd want Manning.

Of course, if Montana was in his prime...