IGN US and Gamespot give MGS4 a 10
We'll let IGN speak for itself:
Is it possible to give a game an 11? If so, this would be the game that would merit that score. Metal Gear Solid 4: Guns of the Patriots is a title that exceeds all of the hype that was attached to the title. Regardless of whether you've seen every trailer and screenshot, read every preview and heard every interview, you won't get a full sense of how phenomenal this title is unless you sit down and experience it for yourself.
Read the rest of it here.
Gamespot's review has the same score, saying the game "is an awe-inspiring synthesis of dramatic storytelling and entertaining gameplay."