Overall: This series isn't for the light-of-heart or innocent ears. It's harsh from it's language all the way to it's characters. If you have a problem with cursing I recommend avoiding the series because you can't go 5 minutes without hearing something obscene.
Story: The story follows a team of pirates called the 'Lagoon Company', who smuggle items throughout the Southeat Asian seas. The team take on a variety of missions that usually result in gunfights, hand-to-hand combat, and/or sea battles. The story is pretty much consistent throughout without any real overlaying plot. This is not one of those series that get's increasingly complex as it goes on, winding it's way towards an eventual end. Black Lagoon's plots are given in arcs. Each arc is made up with two or three episodes during which the Lagoon Company complete their current job.
Animation: The art itself is wonderful, very detailed though the characters come off as simplistic sometimes. The animation is rough though. It's not fabulous but it's not bad enough to deter you from watching.
Sound: The music is a wide range, from poppy beats to hard rock and all things in between and is always appropriate for the current events of the story. My problem is that the sound effects are louder then the dialogue a lot of the time, or at least, that was the case while I was watching it.
Characters: The show offers an interesting collection of characters. You have 'Benny' the computer geek, 'Dutch' the intelligent, reserved warrior, 'Revy' the hot-headed tomboy, and 'Rock' the emotional tag-along. All and all it's not too unexpected, you see similar groups in other animes whose plot circles around a small band of warriors. They are all likable in their own way but a bit one sided at times, though as time goes by you get snippets of information about all of the characters.