I posted this or something similar many pages ago, but as to who is the best NFL QB of all time it is probably the most subjective arguement in all of sports.
I am 44 years old and remember the entire careers of both men very well, and go back to Bradshaw, Stabler, et al and personally I wouldn't include Joe Montana in my top 5.
First, if you are going to base it on championships there is really no arguement against Otto Graham. Otto played pro football for 10 years, played for the championship in all ten years and won 7. Otto's career record? An astonishing 105-17-4. Here is his ESPN obit from a few years ago
http://espn.go.com/classic/obit/s/20...7/1688946.html
But Otto was before our time. If you only want to consider Superbowls (and not previous NFL championships) on what basis would you rate Montana over Bradshaw? Montana played against inferior teams in every Superbowl he played (was a significant favorite in each) Bradshaw faced a hall of famer on the other side in 3 of his 4 superbowls (Tarkenton and Staubach twice). The year before Bradshaw arrived the Steelers went 1-13. In his 14 yr career Bradshaw's Steelers won 8 division championships and 4 Superbowls.
Joe Montana played in probably the worst division in the NFL for almost his entire career. The other teams while Joe were there were terrible. and yeah, Joe won 3 Superbowl MVP's but the first one he was 14 for 22 for a whopping 157 yds and one TD (he did also rush for one). Not exactly a huge performance. Whipping Elways Broncos 55-10 is another matter but the SF defense was also outstanding.
Joe's career statistics are pedestrian to say the least. He only threw for 30 TD's or more once in his entire career. He threw 20 TD's or less in 10 of his 16 years. He was as fragile as a little girl, often injured. To be fair, Bradshaws TD totals were low compared to modern times too BUT very high when compared to other quarterbacks of his era and under the rules they played, which were different than those in the 80's.
He benefited from Walshe's innovative "West Coast Offense" that was new and difficult to defend. His passes were typically short and high percentage. One year his leading reciever in terms of receptions was Tom Rathman.
Joe was also blessed with all pros and hall of famers up and down both sides of the ball. Outstanding support players on offense and great defenses.
If you put Marino or Elway as QB of those teams they likely would have won 10 straight superbowls. Certainly they would have won more than four, IMO.