Re: How are you watching the film?
Star Trek had a few fun moments in 3D (the spears getting thrown at Kirk and Bones in the opening sequence), and Oz looked pretty good in 3D.
But 3D added nothing to Iron Man 3 or Man of Steel. But the only way to see them in IMAX, had to include the 3D.
Oblivion was in 2D, and it looked great in IMAX. Unless there's an especially good reason to have the 3D, there's just no need for it.
"You change the world when you change your mind.