Of course it's a great game, it is metal gear, but for someone who played all the other mgs games this one is unique.
I could talk hours about the awesome graphics, the great gameplay or the well written dialogues. But that is not why MGS 4 is so good.
This game is good because of the meaning to the series.
If have, like me, grown up playing MGS this game will make you cry in the end. The game story has a climax where fans of the other games must not miss.
The only purpose for this review is to just say:
This game is for fans! If you didn't like MGS 1, 2, 3 or any other just don't plays this game, your conclusion will be that the game "isn't so good as people say" or you will curse fan boys for "overrating it".
Guess what: This is a game for fan boys, this is a sequel, this is only a part of the complete experience Hideo Kojima made for gamers.
So keep your troll comments to the call of duty series (which is great, but no MGS).