I´ll start with overall: Don´t buy it if you´ve got important things to do! If you liked the original or Pirates! Gold, you´re running a mayor danger of getting hooked and not realizing how fast time goes by.
The boarding fights are repetetive, animation- like, but nicely done. I like them, as all other animated scenes (meeting the governor, dancing etc.).
The ships and sea battles, well, they DO look a bit weird to me, but I´m not much in the way of a graphic´s buff, I´ve got no big problem with that. To one who is, it might be one, though.
The menus are a bit dry, I liked the way Pirates Gold did it better.
If I were to make a suggestion, go into a video store and borrow it for one weekend and play it. If you don´t like it, you haven´t lost much, do you?