Well, it's quite tough to put the main 3 in order. I mean I love them all. I guess MGS3, then a tie in between MGS2 and 1. Since I wasn't part of the group who hated Raiden and the long cutscenes.
The bosses were great!
Some of the bosses will be talked about for years to come I think. Any to surpass The End fight? Hmmm. Well, some of the bosses are evolutions of previous bosses maybe? Or a mixture of two. It's hard to explain without going into detail.
Some bosses are very nostalgic and do delivery on fanservice.
This game, does however, have one of the most epic fucking boss fights ever in my opinion.
Story wise, I think Hideo Kojima did an utterly fantastic job of tying all the games in the series, and making them into a true saga. The story DOES end. This time, I think there is no excuse whatsoever to send Kojima death threats and shit. I think this game is his game for the fans, it truly is for the fans, and asking for more MGS games will just become selfish in my opinion.
The sound, well, I had the pleasure in playing this in 5.1 surround sound. Oh my fucking god, it sounds incredible. Any reviewer giving the sound less than a 10, needs their ears examined. It sound's incredibly. And with the music, you have the most film like, cinematic game ever created. To me, and this is just my personal opinion, the production value, music and over all epicness can be compared to Return of the King. (LOTR being my favourite film series).