Eh. Not bad. Just played through the tutorial missions (an hour or two). Feels a lot like Sid Meier's Pirates, but a bit less... I dunno. Just a bit less. Almost feels like this was what somebody on Sid's team wanted to do with that game, but split off and did their own thing instead.
The big differences aa that there's no "battle map," (when you meet another ship, you just start shooting, you don't run into it and then get whisked away to the enconter grid) and you actually have to walk around town to do things, as opposed to just clicking around town to access the buildings. When you meet a ship on the ocean, you just start shooting.
If you've never played Sid Meier's Pirates, I recommend this game. If you HAVE played Sid's game, and wish it was just a little bit different, give this a try. Overall I'm disappointed that it's so much like SMP, but it's not a bad game; it's juts not worth playing this AND Pirates.