I saw it recently and enjoyed way more than I expected to. Funny enough I really do not care for the first 2 films so much, and thought the third was okay but I am a sucker for pirate movies and the production design and effects on these films are top notch. What I disliked most about the first 3 was amount of screen time that got spent covering too many weak characters and plots. Stranger Tides drops the dead weight of Keira and Orlando and allows the focus of the film to fall on the characters that everyone like best, Depp and Barbossa (too bad Davy Jones couldn't be in this one). I have to give credit to Depp for stepping up the plate and not allowing a weak moment performance-wise throughout the film. And I have to give credit to the screenwriters for doing a very brave thing: they refused to give Jack Sparrow an opportunity to 'change'. The ending choice he makes w/ Cruz on the island was terrific. This almost never happens. A movie like this by any other studio would have made Sparrow fall in love w/ Cruz and ended with him surrounded by little Sparrows. But amazingly Stranger Tides recognized that the core of Sparrow is he is a constant, a trickster, and as such never changes but impacts other characters (the fountain cup swap for instance). Anyhoos I could go on, but it's very rare that the main character is a trickster that never changes, so kudos to them. I think that's why I liked this one the most.
Also the twist with the Spain's reasons for finding the fountain was neat and pretty funny. Nice shout out to the catholics.
