Here's my opinion. Prince Caspian was a great movie. There were some ways that it was better than the first. The special effects were stunning. There were more laugh-out-loud funny moments. It really was was a great movie. So why didn't I like it as much as the first one? Probably for the same reason that I didn't like the second book nearly as well as the first. Behind all the fantasy and epic battles, the story behind The Lion, the Witch and the Wardrobe is Lewis fantasy version of the biggest story ever told. Aslan the Lion lays down his life to redeem Edmund's betrayal and rises from the dead to defeat the forces of evil. Hard to improve on that plot!
I read that the movie people were actually thinking about skipping Caspian (which is kind of a bridge story to the rest of the Narnia series) and going straight to Lewis' third book, The Voyage of the Dawn Treader (now in pre-production for a 2010 release). They did Caspian because it is the only other book to feature all four of the Pevensie children. Well, I'm glad they didn't skip it! Lord willing, well be right there in 2010 to see the next one. And we'll buy the DVD when it's out. We just might not watch it 5-6 times like we have the first one!