i like 3d a lot when it's done well, but some movies it adds nothing, and in some cases can detract from the experience. but 3d was awesome in avatar, 3d animated flicks, and jurassic park is probably the best "live action" 3d movie i've seen. either that or gravity.
when i saw godzilla in 3d, the screen was all dirty or had scratches all over it. because of that, it was hard to focus and see the 3d because my eyes kept focusing on the scratches during bright scenes. you couldn't really see the scratches/dirty stuff during darker scenes, but in bright scenes it kept messing with my focus.