I just finished the game, and it's easily one of my top 5 games ever played. The story is something unforgettable... I've never felt so connected to the characters in a game, so emotionally impacted when something happens to them. I've never found myself doing things like actively getting angry at one before, only to have to step back and consider... How could they feel any other way? Would I do any different? SHOULD I really do any different? The ending makes you really question the world and humanity, the choices we make, the power we have, or rather the power we DESERVE to have, over each other and the world.
That's easily the best aspect of the game. But the gunplay is also superb, the stealth elements and AI are top notch, the crafting and looting system is very fun and interesting, and the game rewards creativity and intelligence greatly. Not to mention it's the best "real" looking console game ever made in my opinion, the voice acting is absolutely stellar, and the cutscenes look damn close to a live action movie.
There's nothing else like it or even close. I hope I never forget it, everyone who can should play it and everyone who does should stop to think and appreciate what it has to offer.