I'm voting for the unemployed VFX artists that will be protesting the event. Oh wait....
In that case I'll go with Gravity. None of the other movies integrated the VFX, Cinemetography, and Story together into one integral piece as well as Gravity did. I'll add that none of the other movies were as dependent on the success of the VFX as Gravity either.
Pacific Rim should have been in this. Like Gravity, a large part of the success of Pacific Rim was the VFX. The movie is a master class in how to deliver massive objects on the screen with scale and weight.
Between the two it's a coin flip, they both simply nailed it.