John Elway led his team to five Super Bowls. When they won (third appearance), the NFC had won 14 straight Super Bowls. Pretty clear to anyone watching the game during that period that the NFC was vastly superior to the AFC. When you factor in the lack of talent surrounding Elway, the fact he got there three times without a legitimate running game is pretty incredible.
His performance was steady throughout his career. When he finally got the missing link, he won two rings.