I've just seen it this evening. I haven't read the book.
I had the same reaction as I did to the LOTR films - I didn't dislike it, but I didn't particularly like it either - it was just a bit of a non-event. I thought it was very flat emotionally, and humourless. The CGI animals were well done, mostly, except I couldn't take the ice bear seriously every time he was shown from the back with that big furry @rse (maybe there was some humour after all) (and he talked like Doctor Who and made me think of Glacier Mints and Cresta). Are the ice bears supposed to be kind of moronic macho types?
It semed to be trying very hard to look and sound like the Harry Potter films, with a bit of LOTR, Narnia and Pirates of the Caribbean thrown in.
I couldn't really see the point they were trying to get at with the story. Maybe you need to have read the books.
It was accompanied by the most depressing collection of trailers I've ever seen - Bee Movie, Alvin and the Chipmunks, Enchanted and Saint Trinians - they all looked ghastly.