I went with the kids to see Tangled over the weekend. It was excellent, probably the best non-Pixar Disney movie in recent history.
I experienced 3D for the first time, and had mixed feelings. On one hand, it worked very well in many scenes. It seemed to break down a bit when the effect was used to try to make objects look very close to the audience. And the 3D version of the Justin Bieber biopic preview... ugh, nauseating.
It was neat. Maybe even worth an extra $3, for the right movie. But not for Justin Bieber.