A nice trip down memory lane.
The map is the same as it was, for the most part (I haven't gone back to compare island for island). The ship-types were expanded a little. The interaction at the ports remained true to the original. And there were some nice mini-games added on.
As far as the gameplay is concerned, I thought it was fantastic. The updated graphics make the sailing and sea-battles a real treat. The tweaks to the sword fights were nice, but very subtle. And the new "sneak out of town after getting caught" game was..... cute.
The downside to all of this was the lack of that old magic. I'm not sure whether it was the fact that I'm much older than I was when playing the 1st Pirates, or if the game somehow didn't have that certain something. Either way, after a few hours of playing I couldn't shake the feeling that I was grinding through the quests to simply be done with it. Kind of sad really, I expected much more.
After considering it, it's probably a matter of being spoiled by so many excellent and immersive games since then. In it's day, Pirates was a pioneer of open ended gaming; but now, it has to compete with games that are either far more massive or far more rich in detail (or both).
Of course, in the end, this game is a very good one and I could recommend it to those wanting to plunder the Caribbean. At the price you can currently find it, it's still a bargain ($20 download at a couple sites).