Eli Manning is like Trent Dilfer. He's a top-10-ish QB that is much closer to 10 than 1. He's good enough that if he plays well - not great - and the rest of the team around him can play great he will win a Super Bowl. He has won 2 Super Bowls using this schematic.
I do think Romo is a better QB than Manning, and had he been a Ginat hge may have won more Super Bowls than Eli has.
The year Eli won his first Super Bowl the Giants beat NE for the title from a duck pass by Manning that only was completed by luck (and a great play by the WR). In the same playoffs, the only reason the Gaints advanced is because htey beat Dallas in a game where the Cowboys special teams and defense kept giving away the lead charged by Romo and the Cowboys passing attack. Even then, it came down to perfect pass from Romo to Crayton where Crayton stopped on the route and it fell incomplete. If Romo's receivers did what Eli's did in those playoffs, it would have been Romo, not Eli, advnacing in the playoffs. In other words, Crayton and Ginats receivers - and Dallas' poor defense - have more to do with Eli winning his first Super Bowl than Eli himself does.
This is how I define the differnece in loss and defeat between the 2 QBs using that season as an exsample. In one case, you have Tony Romo, a better QB making perfect throws that kill his Super Bowl chances because of sub-par receiving and defenside; and in the other case, you have Eli Manning, a not-as-good QB making marginal throws, but that translate to Super Bowl succes because of ecellent receiving and defense.
You can actually fast forward to last season and look at the play where i the second Ginats game where Miles Austin lost a perfect pass from Romo in the lights. If a Cowboy receiver does not screw up that play - again in a game where the Cowboy defense and special teams were out to lunch - then the play is completed and Dallas moves on to woin. Once again, Miles Austin and Dallas' poor defense have more to do with Eli winning his second Super Bowl than Eli himself does.
The numbers do not lie - as Toomer pointed out - but I argue that the circumstances do not lie either.