So far I'm in 10 episodes and this is really turning out to be a good series. Its a slice of life/Shojo/sci-fi anime that so far has been pretty good story wise. At times its a bit heavy on the 'girl crush' aspect and there has been a fan service episode (they literally teased it as 'the next episode is a swimsuit episode... gotta give the fans what they want!'... God damn it Japan, don't ever change!) But it was not as bad as it could have been. I really hate fan service episodes... I have no need to cartoon boobs.. so I skipped out 80% of the episode (ok Japan, if there is ONE thing you need to change it's your obsession with cartoon boobs).
There already seems to have been a spin off of one of the characters, but I didn't watch it yet... still going through Railgun.
Good show so far.. opening and closing themes are pretty good, average animation, and better than average stories/plot. The first 4 episodes are dubbed (on Hulu or Funimation) but the rest are subbed... from my very, very basic understanding of Japanese the English sub loosely follows the Japanese dialog... and the Dubbed version changes it even more.