I played a little bit of Pirates of the Caribbean and I can say it has its charms, and it would probably be playable if it weren't for absolutely terrible combat system! Basically, all you can do is swing your sword at the opponent and try to dodge his attack, but it's so lamely done that it reminds me of playing Barbarian on C64. Other than that, the game seems to be pretty good. You have absolute freedom of movement and a huge gaming world (like in Morrowind), there are also some RPG elements, but it lacks the atmosphere and possibilities of Sid Meier's Pirates. Stupid enemies like skeletons (I assume they were added because there are skeletons in the movie) spoil the setting, and ability to explore entire islands is seems to be more of an eyecandy than a real addition. IMHO, Morrowind is a much better game.
All in all, I'd say you shouldn't pick up Pirates Of The Caribbean. You will probably just end up frustrated and hating Disney for ruining what could have been a great game.