It comes down to this: Quarterback is the most important position and no quarterback was more accurate or cooler under pressure than Montana, who led the San Francisco 49ers to four Super Bowl titles. Montana threw for 300 yards or more 39 times in his career and led 31 fourth quarter, come-from-behind victories. Montana's confidence came from maximum preparation and it showed when the game was on the line. That was put on display in the 1981 NFC Championship Game when Montana's last-second TD pass to a leaping Dwight Clark sent the 49ers to their first Super Bowl. It also became one of the most iconic images in sports history. As of 2010, Montana is one of six quarterbacks in NFL history with multiple Super Bowl triumphs on his resume who is also undefeated in the big game. Montana stands atop the mountain with his performance in those games. He completed 83-of-122 passes for 1,142 yards with 11 touchdowns and 0 interceptions and a passer rating of 127.8.

On the Other: RB Jim Brown

Jim Brown was the best running back in NFL history. He retired on top of his game after nine seasons after having been named an All-Pro eight times. How good was Brown? He rushed for 1,863 yards in 1963, 1,446 yards in '64 and 1,544 yards in '65, the last three seasons of his career. This was done when the NFL played 14-game seasons and 1,000 yards was considered a significant achievement. He rushed for 12,312 yards in his career and that mark stood as the NFL record until Walter Payton surpassed it 19 years later. Brown averaged 5.2 yards per carry, 104 yards per game and he was so tough and physically imposing that he never missed a game due to injury in his career. "My arms were my weapons," Brown told NFL Films. "If you tried to tackle me high, I'd use my arms to change your mind. If you tried to tackle me low, that was your choice. It usually didn't work out so well."

Bottom Line

No player at any position--let alone quarterback--ever played better than Montana when the championship was on the line. That's what set him apart. He was 4-0 in Super Bowls and the record shows that each performance was scintillating. He never had a passer rating lower than 100.0 in any of his Super Bowl wins and he never threw an interception in any of those games. Not only was Montana confident in himself, his coaches and teammates had ultimate confidence when he was on the field. He delivered every time and that's what separates him from Jim Brown and the rest of the competition. Brown played before the Super Bowl era and only won one championship in his nine years. He was a great player and the best running back who ever played, but you have to give the edge to the best quarterback who ever played.

Source:

Pro Football Reference: Stats and History

NFL.com: NFL Stats