[MCoxon]

I agree with Matty C's point that we need to agree on what we're solving for when we say "best." I also think we may sometimes overly focus on stats and that we should take into account non-statistical evidence as well (and I'm an economist and businessman). For instance:

1) Number of championships. Even this can be hard to use because great teammates can make one player look great (e.g., Mantle).

Did Ted Williams never win a WS because he didn't have "it"? Or because his teammates weren't good enough? Or because Mantle and the Yanks were too good and kept the Red Sox out of the WS altogether for 12 of Williams' seasons?

Mays and Aaron each only won 1 WS. They had HOFers all over the place as teammates. Spahn, Mathews, McCovey, Cepeda, Marichal. These aren't nobodies. 1 WS each, both when they were in their early- to mid-20s. Why?

2) Club house leadership. I always see someone traded 5-6 times and wonder, was that random, or was he a club house cancer? If someone gets traded every few years, you have to wonder if he just can't get along with teammates, coaches, GMs. That should be considered, as it also influences the ability to get the best out of teammates and ultimately the team. Rico Carty got in fights with Aaron and Santo and had to get traded from the Braves and Cubs because of it, in spite of being a great player on the field (e.g., 1970 Batting Championship with a .360+ avg.)

Point #1 and 2 can be summed up by Barry Bonds - I lived in SF for a lot of his time there. His stats (forget PEDs for the moment) say, at his peak, he was a top 2-3 best hitters ever. On dimensions #1 and 2 - not so great.

3) Play under pressure. Sabrematricians laugh at ERA, but I always feel like advanced stats (especially pitching stats) can mislead on whether a pitcher performs in the clutch. There's a difference between winning a 2-1 game against the other team's #1 on the road in a September pennant race game vs. putting up WHIP numbers in the 5th inning of a meaningless game, when you know you're going to get pulled after 100 pitches, against Tampa in August.

I cringe when I see "greatest game ever pitched" -- as happened sometime earlier this year -- and it was some Tuesday game in April when a guy gave up 2 hits but had the best index of god knows what. No - "the greatest game ever pitched" is throwing 10 innings of shut out ball in a 7th game of a WS (Jack Morris), or throwing perfect game in a pivotal 5th (or 6th, can't remember) game of a WS (Larsen), etc.

So this is a great discussion on statistics (and I love, love, love statistics), but I think there are many non-stats ways to gauge performance, too.

Using the above criteria, it's still a toss up to me. Mantle won tons of championships, was universally beloved by teammates, and played amazing under pressure (18 WS home runs). Aaron also played under pressure - maybe better than anyone in baseball history. I think for that alone, he deserves a lot of credit