I've just finished it. I didn't buy it right after the release because I actually had to play the first game first
never owned a PS3 and had it on my PS4 bucketlist for way too long, but playing 1 and 2 just after each other was a good thing I think. I never had to wait for the second game and build up super-crazy expectations, and looking back, I can't really say which one I liked better.
I feel both of them are masterpieces in their own way though and I think they are pretty even in terms of quality. I really haven't seen immersion like this before in a video game, they really suck you in and make you feel a lot of emotions. I didn't even enjoy the fighting all that much (doing it stealthy is always gratifying though), but I really liked scouring everything for items and I think the storytelling and characters are outstanding.
And although I was pissed when the game made you switch characters, I do appreciate it now that the game is over. It's a gutsy decision, but I felt getting the other perspective and seeing the other side of the story was well worth it. They could have played it safe with the protagonist/antagonist thing, but they actually challenge you to reconsider the whole good/evil and right/wrong thing. You don't get to see that very often and I honestly enjoyed that a lot.