It caught me completely off-guard, but with the way Abrams has been handling Spock, I should have expected it.
I would much rather have seen him grit his teeth, cry a single tear, and unconsciously crush a nearby object before standing up, whispering "Khan" and striding off with full intentions of destroying the man who killed his best friend.
Sarek to Spock: "Emotions run deep within our race. In many ways more deeply than in humans. Logic offers a serenity humans seldom experience. The control of feelings so that they do not control you."
Since the loss of Spock's mother, planet, Pike and more... Spock has been holding back those emotions. He admits this in the shuttle to Uhura as they are heading to Klingon homeworld surface. At some point Spock will hit the breaking point where all those deep emotions must surface, in this case the death of Kirk.
I lost my dad February 18, 2011. I held it together because while everyone else was grieving: I made his final arrangements; kept my stepmom together; dealt with the hospital, funeral home, finances, etc. I was "emotionally compromised" and, eventually, after everything was done I broke down and cried uncontrollably.
We all reach that point eventually... as did Spock when he cried for Kirk and screamed, "Khan!" This time around, I felt the emotion much more deeply than TWOK (heresy, though that may be to some). It did not seem nearly as contrived as it did in TWOK, the emotional build-up was there. The plot prepared us for it, as I mentioned above.
I saw the movie today in 3D with my brother. Tonight, we discussed it in more detail. He only saw TWOK once quite a while ago and only vaguely remembered the scene, but also thought it was better done this time. He's not even a Trekkie!
No one in our theater laughed nor even scoffed at the scene today. The family seated in front of us commented afterward that it was done better this time around. My brother was heard to say, "If they keep making movies like this, I'll have to become a Trekkie!" (He tortured me for years about liking Trek.)