Quite simply the best anime I've come across (and I have a large collection!). The music, visuals, voice acting, storyline, atmosphere, it's the best thing to happen to the genre in years.
The production of this show is amazing, it relies on the characters personalities to drive the story rather than large chested bouncing and over the top voice acting. The story isn't as overly intricate as series like Ghost in the Shell 2nd GIG but it's still just as engaging and thought provoking, you aren't weighed down with 20mins of excessive dialogue. Unlike other shows it doesn't feel the need to recap all the time and it has a linear storyline so each time you watch an episode you can feel the progression of the story rather than stand-alone episodes that add nothing to the arc. I watched this whole series in japanese with english subtitles soon after it finished airing in japan and I've been waiting aaaaaages for it to get to DVD.
Best of all, the intro and credit music actually reflects the show, quite often I'll just let it run through rather than skipping…and I don't even like Radiohead!! I've found that many anime series seem to lack this feature – Elfen Lied was a good example, such an ultra-violent depressing show but the outro music was totally out of place.
I recommend this series to EVERYONE!! Even if you get hold of the jap version now you will end up buying it anyways just like me.