It's a beautiful game, but the controls are horrible and it just seems incredibly rushed.
For a better version of this game, check out Sea Dogs (PoTC was originally gonna be Sea Dogs 2, but they ended up naming it after the movie and rushing the release to the movie release date). Also, Pirates! Gold for the Sega Genesis is an example of this genre done right.
People often compare this game to morrowind, because it was made by bethesda, but it's really not like morrowind. The storyline of the game is much more linear than morrowind, and the world isn't nearly as huge as morrowind. I would consider this game to be more like a "Freelancer with boats" than like morrowind. Sadly, the game was rushed out and the gameplay suffers horribly because of that.