I saw it last night. Overall, I thought it was very, very good. Not quite an absolute classic - I don't feel the need to watch it again anytime soon - but a really good movie experience. Everything just worked really well together, and the visuals were absolutely amazing. It is a perfect marriage of Neil Gaiman's imgination with Harry Selick's imagination, and it is both beautiful and creepy.
I saw it in 3D, but I felt that the 3D added little. Not nothing - there were a few scenes where the 3D did allow for some cool effects (the opening credits, perhaps, the best example), but I think that the experience in a 2D cinema would have been virtually identical as far as the main selling points of the movie. Which is just to say - if you can only see this in 2D where you live, don't feel like you're missing out on something important.