There's an overly-sarcastic review of the film here. It runs over two pages.

However, based on my experience of the previous films, and of having read and loved the book, I'm quite prepared to believe its verdict. Basically, it says the book is long and rambling, but it needs to be in order to lead up to the flash-bang-wallop finale. The film should have gone: 1) set-up, 2 ) finale. But by splitting the story in two, you're getting an over-long prequel to a climax which won't be here until another year's time.

I think I might wait a year, then watch Part 1 on DVD in the afternoon and Part 2 at the cinema in the evening. If I still think it's worth it by then.