I just finished the first 4 episodes. Keep in mind that I only skimmed over the Animenfo description, as it seemed to have spoilers.
So far, I'm liking it alot. The animation has a very old-school look to it that reminds me of Giant Robo or Future Boy Conan, and I like the style. The show itself is very mysterious, melancholy, and creepy at times. It also has some intense, nicely animated, and well coreographed action scenes.
The story is getting pretty interesting and there's alot going on so far. The show covers alot of time periods and locations, from the mid 1800's in Holland, the early 1900's in Sweden, and the near future of 2012 in South America, and there are a group of children who, for some reason, have survived through all of these times.
If you're looking for something with a mysterious and complex story, I'd recommend checking it out. It can't hurt. On the other hand, if you want mindless fun and entertaining eye-candy, you should probably look elsewhere.