I saw it in 3D yesterday (begrudgingly, as I hate 3D, but the theater I went to only showed it in 3D). The 3D is used to pretty good effect for the most part (ie: it's not 20 minutes of normal footage and then a gratuitous 3D shot of something being waved at you), and I found that about an hour into the movie, I didn't notice it.
What I thought was odd was that there were things in 3D that were just part of the background (like there was literally a scene or two where the railing on a walkway was jutting out in 3D).
If you've already seen it in 2D, I really don't think you missed out; but if you liked the movie (and I thought it was very very good) and were going to see it again anyway, the 3D doesn't ruin the experience.
What I thought was odd was that there were things in 3D that were just part of the background (like there was literally a scene or two where the railing on a walkway was jutting out in 3D).
If you've already seen it in 2D, I really don't think you missed out; but if you liked the movie (and I thought it was very very good) and were going to see it again anyway, the 3D doesn't ruin the experience.