It is so hard to write about a game that has been talked about for so long and about a series as legendary as Metal Gear Solid. It is even harder to explain how MGS4 is an experience that goes beyond any other game I've ever played. There's nothing out there that even compares to this game, the graphics and cutscenes are phenomenal, the soundtrack is an instant clasic (I still have the "old snake theme" carved in my brain), the voice acting is amazing and the story is... well... typical MGS. Kojima has also been able to give Snake's story an ending. Whether you are happy or not, it is over and he managed to tied many loose ends in this game.
If you have a ps3 and haven't tried MGS4, you owe it to yourself. It will be hard for a game to top what this one has accomplished.