I loved this movie and I can't wait to watch it repeatedly until I am sick of it.
The main thing I feel you should know going into it. The book was written for "young adults", so it's not written to be a very thought-provoking movie. The story is simple and predictable. If you have fun with dystopian movies and can accept that the story and dialogue aren't the best, but the concept of the Mortal engines universe is interesting; then I suggest you see it and have fun with it. If you don't want to gamble the money of a movie ticket, then wait till you can rent it.