I went to a matinee and the 3D was the same price as 2D. Based on some recent 3D movies, the 3D in this one wasn't up to par. I'm glad I didn't pay extra for it, as there weren't many effects that utilized the 3D. I recommend skipping the 3D for the extra cost.
Movie was great, though! It followed a predictable plot, but still a fun movie for families.