What I really hated: Slow storyline, left our important details
Hopefully years later they do a remake of it. Overall its just average, not as intense as the book. They left out Alice's history, which sucks. New Moon will definitely be better(just by comparing the trailers you can tell).
For someone like me who doesn't watch gory/horror movies(prefer watching it at home), I think its great. The gory was just right for me, but the suspense wasn't. The ending wasn't that good and there were a few unanswered questions. I tend to mix this movie up with Rule #1 and I personally prefer Rule #1 although both endings, kinda can't make it for me.
I watched it at GV Vivocity. Before the movie started, there was an advertisement on Christmas Carol(3D). You can fully compare and note the differences between it. Not much effect at all. I will advice you to save the money and not watch it in 3D.
Overall its just something you pay for the sake of watching.