Oh man. I really loved this game. Came in as a definite Metal Gear fan, but Phantom Pain is really the epitome of the series. Still has some Kojima craziness, but a more appropriate amount. The plot does not make a ton of sense, but I actually found myself enjoying the themes of language and legacy/identity. While I’m still not sure if Quiet was supposed to be satire, wish fulfillment, or some combination of both, I even found myself enjoying the relationship between her and Snake by the end of the game (not as much as the relationship between Snake and D. Dog though.
In terms of pure stealth gameplay I do not know of a more enjoyable experience. Really well constructed environments that allow for lots of choice in how to approach missions. Difficulty/AI almost always felt appropriate in that when you died it felt like it was because you messed up and not that the game was unfair. And, a much longer game than expected. I did take a lot of time to go through side quests, and build up my base, but even just the standard story took up a significant portion of my time (and, a lot of later missions would be very tough if you do not take some time to develop your arsenal and sidekicks).
Yes, the game is not perfect, and it is a shame that the final act did not get the completion it deserved, but what a great note for an iconic series to go out on.