This is saying a lot because for the most part, I can turn my nose up to Index if I want to. It certainly wasn't a bad show, but as I said in my review of it, it was disposable eye candy. Nothing particularly memorable. For the most part, Railgun would have been the same if it hadn't made up where Index failed.
The character interactions alone make this series worth the watch. I love a good "four girls doing nothing" anime when the four girls all have their own different ways of interacting with each other and when none of the girls are stereotypical archetypes. Even though Kuroko is batshit lesbo for Misaka, that's only one side of her personality and we see many different forms of interaction with the other girls. With Uiharu, she plays a capable mentor to her lack of confidence, and so long as she's not around Misaka, she's as normal as any of the other girls. Likewise, Misaka goes totally tsundere when Touma makes a cameo, but she is not ruled by her tsundere qualities. She has a strong sense of justice that makes her narrow-minded in certain situations, and she keeps a lot of her personal preferences guarded from the others. As a "four girls doing nothing" series, it works, but it doesn't stop there.
Once in a while, Railgun decides it wants to have a plot, and when it does, it goes into it heart and soul. This is even more fascinating because the final stretch is 100% filler and yet it brings all the character growth and final revelations to the table that one expects from a solid conclusion. If no one had told me I was watching filler, I would have believed this was canon material. It is just that good, so good that in fact I'd say it makes up for the consecutive standalone fanservice filler that preceded it.
The technical qualities are still as good as Index, with the voice acting being even better. The voices were unique and done well enough that they felt like genuine performances and not just throwaway roles, especially Uiharu's from Aki Toyosaki, a seiyuu who I am genuinely starting to warm up to despite a rocky introduction to her work. But I digress.
Railgun isn't the best anime. It doesn't have the best anything for that matter, but it does have a lot of heart. It cares about seeing the relationships of the four girls grow. It cares about having a plot that's always there, though not always the focus, and tying up all the loose ends rather than saying "LOL WAIT FOR SEASON 2" at the end. But above all, it asks for nothing more than to be enjoyed and it does so without excessive pandering. Given how much anime is tailor-made these days to certain fetishes and archetypes, that is nothing short of wonderful.
Overall, I give To Aru Kagaku no Railgun an 8 out of 10.
