Went to see this last Thursday with my younger brother and thoroughly enjoyed it. We were the only two in the cinema, as we went in the morning and the vast majority of schools had already gone back, so that was doubly fun :)
The dragon was very impressively done, as were all the fantasy creatures. Eustace made me chuckle, and Lucy and Edmund, along with Caspian, were all well portrayed and developed. A great installment to a great trilogy--I hope they don't stop with this one just because Lucy and Edmund are no longer featured.
My brother, it must be said, has subsequently said he thought it lacked a bit of action and could have done with some more excitement. For my part (and I have only one movie that doesn't feature either an explosion or a fire of some description--that being Amazing Grace), I thought it had ample.
My favourite character remains Reepacheep (and this was true in the books as well), although I'm also rather fond of Prince Caspian. The characters were all more developed in this film, probably because there weren't quite so many of them to deal with. Eustace in particular proved a strong addition to the cast--although it wasn't until the end that he was a strong person! His moaning provided plenty of amusement, and was a good counterpoint to the enthusiasm of Lucy for her return.
It's well worth taking the time to go and see this film. A thoroughly enjoyable experience, with a wonderfully memorable ending.