Montana was the QB on a team which, in each of his 4 SB appearances, was CLEARLY better than their opponent. Only in one of those games, in 1988, was Montana forced to execute a last minute TD drive to win the game- which to his credit, he accomplished. Very few QBs have even been in this situation. Big Ben has been in it twice: 2 years ago, he led his team to a victory. Yesterday he didn't. Who knows whether Montana would have been successful the 2nd time around?
Tom Brady has also led his team, in 2 SBs, to last minute victories. Kurt Warner appeared in 3 SBs and each time directed his team to a game winning or game tying score in his final drive, yet he is not given the credit Montana is because he was not the last guy to have the ball in his hands and as a result lost 2 of those 3 Superbowls.
I think Brady and Warner (and Steve Young) were all better QBs than Joe Montana. Montana was a fine QB, but also one of the luckiest to ever play. That is his ultimate legacy.

How quickly we forget.
The 49ers were demonstrably better than the Broncos in Super Bowl XXIV, no question.
However,
1988 Bengals were 12-4, scored 448 points, allowed 329 points, had the 2nd best differential in the league (7/4 p/g)
1988 49ers were 10-6, scored 369 points, allowed 294 points, had the 6th best differential in the league (4.7 p/g)
1984 Dolphins were 14-2, scored 513 points, allowed 298 points, had the 2nd best differential in the league (13.4 p/g)
1984 49ers were 15-1, scored 475 points, allowed 227 points, had the top differential in the league (15.5 p/g)
1981 Bengals were 12-4, scored 421 points, allowed 304 points, had the 2nd best differential in the league (7.3 p/g)
1981 49ers were 13-3, scored 357 points, allowed 250 points, had the 3rd best differential in the league (6.7 p/g)
Not sure where you get the idea they were CLEARLY better than their opponents in every Super Bowl. In three of the four their opponents were among the top teams in the league, and in both cases the Bengals had better point differentials and in 88 had the better record to boot.