It was worth seeing, and it was worth seeing on the big screen, but I have a definite preference for the first movie. The adaptation cut, changed, and swapped around an awful lot; I felt the jumps and the gaps much more than I did in LWW. To be fair, and as R pointed out, "Caspian" is probably the least cinematic of the books, so it probably took more effort to adapt the story and make it work as a movie, and watched as a simple fantasy battle/adventure movie, it worked well enough. Fortunately, I had heard enough about the changes that I was able to go in with that expectation, so I didn't mind too much.
Also, Reepicheep was just about perfect. So that makes up for a lot.
Probably the thing that bothered me the most, in terms of what was missing from the movie, was the lack of development in the relationship between the characters, and the near-total lack of character development for any of the Narnian characters except Caspian himself. The film actually spent far more time on the development of Miraz and his men than on Trumpkin, Trufflehunter, Glenstorm, Dr. Cornelius... For example, we don't get to see Trumpkin growing close to the children -- we see none of his early doubts, or their conversations about Narnia's past and the reality or lack thereof of Aslan, and so on. The DLF nickname comes up as a throwaway, almost to the point where I wish they hadn't even bothered with it. We get a touching farewell when Lucy parts from Trumpkin, but the emotion between them isn't earned. The movie is forcing us to fill in the gaps, which would be fine if the storyline stuck closer to the book, but it drifts so far in places that I wasn't always sure I could make those assumptions.
Overall, I'm satisfied enough, although mostly because I did go in with lowered expectations. If I had expected as good an adaptation as we got of LWW, I'd probably be disappointed.