I saw the film both ways. It is fine 2 D. Do yourself a favor and see it.
It really is worth it. If you like the books, this one is actually bigger and better than the 1st 2 books, which I just re-read.
After reading the first 2 books again, I can see how the writers and director changed it a bit for today's audience. It IS, and WAs, for the better, in my humble opinion.
Even though they are considering this a flop, I think word of mouth will, and should, actually turn this movie around. I would love to see a sequel.
It deserves it.