Good: The production values, the plotting, and the depth of the story are all fairly impressive. In general, the setting is fairly original, despite how much they rip off from various sources. The pacing is also pretty good, with its two-episode arcs slowly unfolding the world and the main plot for all to see. Darker Than Black is a broad setting, with, I think, a lot that would appeal to both general fans of supernatural suspense and fans of anime in particular. As the American director and localization team note in the commentaries, it doesn't talk down to its viewers. It comes together fairly well in the end, but I'll probably need at least another viewing to figure out half of what was going on.
Bad: The two-episode arc format may not be for everyone. For one thing, it means that we don't get a lot of solid recurring characters, but rather a cavalcade of minor characters who appear once or twice and then vanish. That's not necessarily a bad thing, but it may not be for everyone. The first two episodes also don't do a very good job of setting up the story to come--when the show first aired, I watched them, was disappointed, and left off watching the rest of the series. But when I watched more this time, I got totally hooked. Some people might also find the show's tendency to rip stuff off from the rest of popular culture a bit off-putting, but it didn't particularly bother me.
My Favorite Part: I really loved the way they set up the world and its strangenesses, but I'm a sucker for careful worldbuilding. You know what else I'm a sucker for? Spies. The MI6 team, especially November 11, owned me totally.
Comments: You know those fancy chocolates at organic food stores? You know how you know perfectly well they don't really have anything substantially nutritious in them, but they're so well-made and sophisticated and just so damn tasty? Darker Than Black would be the anime equivalent of that. For the most part coherent themes are crowded out by plotting and character, but there are some interesting running threads about the nature of identity and humanity if you care to follow them. And there isn't really anything wrong with that--this show is more about telling a complicated and mysterious story than about carrying through a message about the world, that's all.
You should watch it if you...
♦ Are turned on by creative use of superpowers
♦ Enjoy edgy urban fantasy/near-future sci-fi blends
♦ Like being able to dig under the surface to see what makes a plot or character tick
♦ Like a blend of episodic and arc-styled storytelling
♦ Are looking for something centered more on events and characters than on relationships between them
♦ Can put up with a good old-fashioned mindscrew on more than one occasion