I knew nothing about this series until I ran into the internet radio page for the series (animate.tv). Even that was just barely in time as the first episode was just about to become unavailable.
The radio, featuring Kamiya Hiroshi and Shintani Ryouko, is face paced and highly entertaining, so even though I had some reservations about SHAFT animation, I decided to pick it up.
Anime is also fairly fast paced, with very impressive casting. All the characters are very distinctive (almost too distinctive) with names to go with their... distinctiveness. I imagine most people will be able to find one or more they can relate to. I can relate to Kitsu Chiri (kicchiri) the most.
Animation is fairly good, if a bit overly artistic. Although I did not read the original works, from what I read in user reviews, it appears that the anime is actually better than the original manga. Maybe "better" isn't the correct word here. It merely works better because of the way the theme lends itself to fast paced flow. It's kind of hard to get that rushed feel from a book.
All in all, I'm happy with the purchase, and will continue with the series. They just announced the second season, though. It makes my life more complicated than it needs to be. Talk about despair.
