It's a 5/5 game for me, going by the scale our website uses. That's not to say it's without criticism, but I firmly believe in the impression left by the sum total of parts, and none of the things I can nitpick about or suggest improving impact that in a negative way. This to me is one of the medium's "greats" that shows what can be accomplished with the right visionaries and talents.
Much like Half-Life 2, Metroid Prime, and Resident Evil 4, I see it as one of those titles that effortlessly springs to mind the moment someone asks "what are the best games you've played". It was just a wholly satisfying and enthralling experience from the very top to the very bottom, and as the credits rolled I felt no sense of dissatisfaction or frustration. A "complete" masterpiece.