Comming from the perspective of someone who has read the book before watching the film I will say this is a good movie.
The characters look exactly as described in the book and the traction cities are just as detailed as the book.
However, there was a significant difference when it came to the ending.
(SPOILERS)
In the book Valentine was ment to fight with Hester on London after she placed the kill code in Medusa. This is when she learnt that Valentine was her father. In that moment he was suppose to pludge a knife into her but instead Kate jumps infront of the blade causing her to bleed out. This where Hester gets into the the Jenny with Tom and they start to fly away. After that Valentine stays with Kate as the whole of London blows up leaving Tom as the only London-er left.
If the company used this ending instead of the completely wrong one the suspense of the movie would have been more of a reward for waiting.