This NY Times article examines Eli through his first 3 full seasons as the NYG starter (48 starts).
Manning is widely being assessed as little more than an adequate quarterback, and a symbol of the team’s current role as a second-tier contender.This chart compares Eli's first 48 starts with those of the other Manning, Brady, Roethlisberger, Palmer, Bulger, Favre and McNabb. Eli is at or near the bottom in whichever stat you value most, including some that aren't listed, such as YPA and adjusted YPA.“Whatever ‘It’ Is, Eli Is Without It,” read a headline over a column in The Record of Hackensack, N.J. A pair of Newsday reviews were topped with “Unfortunately, Eli’s as Good as He’s Going to Get,” and “Eli’s O.K. — That’s the Giants’ Problem.”
In a recent Sports Illustrated poll, Eli was voted the 2nd easiest QB to intimidate, just behind Rex Grossman.
All that said, over the past couple years, there have been several threads here which asked to rank the best QBs, and it's not that uncommon to find Eli listed within the bottom half of the top 10.
I don't feel Eli can be labeled a bust at this point, but as the NYT article notes, whenever the Giants lose a game, the critics come out in force. Not only is Eli struggling to meet the expectations of a #1 overall pick, but he has the added pressures of being in New York, and living up to the Manning name (big brother in particular). Being just "O.K." isn't enough for a lot of people. Assuming the above headline holds true, that "Eli’s as Good as He’s Going to Get", how much longer will he have as NYG's starter?