TLOU- The intro was poignant. It set the mood, got you emotionally invested into the character and story right away and it finished with a bang, literally. I still get

seeing it. Excellent intro
MGSV TPP- When Snake looks at his arm and sees he has no hand and starts struggling, you know shyt hit the fan. Then seeing Quiet come into the room and silently kill the nurse and then the doctor as you just watch helplessly was amazing. The fluidity of that scene was great. It goes on too long though imo since I didn't want to do the whole intro over during that chapter 2 mission.
Going off the pre release impressions of several reviewers and early buyers of
UC4, i'd guess it's another contestant as I see quite a few people have said it's apparently on par or even better than TLOU's intro. I have no doubt since it is directed by the same guys who were behind UC2 and TLOU.