Montana was smart and benefitted from Walsh's system (and throwing to a guy named Rice) as many QB's after him did. He was the perfect player for that system and may not have won with another system. Marino played in a great system too, but never with a complete offense (a running back). All great QB's can win the superbowl if in the right situation. Some do not, because of their situation. However, nobody should put down a QB who clearly has demonstrated greatness because his team never won a SB. To be great is one thing, but who can ask a QB to be all 11 players (or actually all 22 players) on the field? By the way, Trent Dilfer won a superbowl (Ravens ..remember?). Shall we say that he deserves mention among the greats? If Elway had retired after 13 years with no ring would anyone say Dilfer was better than Elway and Marino? C'mon!
So if you want to compare 2 great QB's like Marino and Montana, go ahead, but the superbowl has nothing to do with who was a better player. The only way you can compare with that is to have both guys play on the same team and see how far they go, which is impossible. There are too many variables to conclude about 2 individuals based on how their 40 plus man rosters did.
That said I would take Marino as my best all time, but could not really argue with somebody naming Montana, Otto Graham, Sid Luckman, Elway, etc (but not Kelly..jeese), as long as their reasons were not that they won more superbowls than Marino. If championships are your mark, then clearly Otto was the best - oh by the way, he had a guy named Jim Brown running for him...
