I really think they could have done far better. The two movies before were so much better than this. The main problem I had with this was Eustace. His acting was not what I felt he it be. Plus they changed the actor for Prince Caspian! I liked the actor in the Prince Caspian movie much... better! There are many other faults I can find with it, but since I don't have time right now I won't write them here. It's not the worst movie, but neither is it the best.
Loved the whole series, however this one is by far my most favorite. Just a wonderful story of the Power of the Lord! He took a nerdy, bothersome little cousin and changed his whole outlook towards the older children. loved it.