Went for Imax 3D by going to early show to save the extra charges...As the producer said tell a great story in 2 D and the extra effects are like the cherry on top. As an old guezzer, I guess that the cherry wasn't as spectacular for our group, we all thought the story was great but would have enjoyed it the same in 2D. There were 5 of us that say it together.
Plan on it being long, it would have been nice to have an intermission but by eating before and planning it worked fine without a break, you may not want to leave in the middle.