I don't know where Brady ranks as a QB but he has to be top 5 at least. IMO Marino was a better passer than any of them but on middle of the road teams. If you are going to base QB ratings on big game performance then you have to go with Montana and he wasn't as good a passer as Manning, Brady or Marino. Montana was very good just not in their league.
As far as Manning is concerned he played on some Colts teams that had poor defenses while Brady played on better teams. This could be Manning's last season. He doesn't have the arm he once had after his surgery and he may have problems with the weather and the Seattle defense in the Super Bowl. We'll see.
I generally agree with all of this, especially Marino. But he did have the Killer B defense earlier in his career, and yes he's the best passer I've ever seen, but he was wild during the game in terms of personality. The year the Colts won the Super Bowl they had the best defense in the league with two terrors as sackers, and they carried Peyton through a really bad postseason for the QB. Brady's defenses in the Super Bowl winning years were fantastic, but one thing people missed about the last two super Bowl wins is that the top players all went down from injuries and Brady had to carry the Patriots with his arm. Ty Law, Willie McGinest, Ted Washington, Rodney Harrison, all went down. Remember Earthwind Moreland playing CB? They gave up something like 29 points in 30 minutes to the Panthers.
The big misses for the Patriots were the two Giants losses in the Super Bowl. In both those years, they should have beaten the Giants and choked. If you watch SOUNDFX from the second game, the Giants were saying they had no answer for the Patriots in the second half, and the next thing you know, the Patriots choke on the game winning drive (would have been a 2 score lead) and Eli makes a great pass to Manningham for the victory. Even then, the Patriots almost complete a Hail Mary on the last play with the ball an inch away from Gronk's arms in the end zone.
I am only disappointed the last 15 years by those two Patriot failures. As for the rest, losing to the Broncos this year or the Ravens, etc., it's to be expected, and doesn't really hurt much. Like UConn losing in the F4 in 2009. The worst loss I can remember other than the 2 Super Bowls was the Jets in 2010.