I am posting this general review across :
1. to aru majutsu no index 1 and 2
2. to aru kagaku no railgun
This is one of my favorite series. I havnt read any books, as I normally dont, so I cant comment on how it justifies the transition from book form to animation form. Quite frankly I dont care either.
This series is probably so good because of its setting and its characters. The story isnt that wonderful because half of the time, I dont really get the "religious" stuff they talk about. Even if I was religious (which i used to be), I wouldnt fully understand what they are talking about sometimes.
The setting is in a big city, which is... I think basically a big school and dorm that is at the peak of scientific progress. So, you have cleaning robots that go around, wind mills, etc. There are students in the city that have powers that were indouwed upon them somehow. They have potential to have a certain power (teleportation for example), and this city brings out that potential. They use the powers through imagination/projection of thoughts. Mixed among all the science/technology, you have religious groups from there and around the world that seem to clash there often. Railgun is basically a close up on the daily lives of the girls. kuroko shirai, misaka mikoto (biri biri as touma calls her (or her power name: railgun, since she can control electricity, she can launch objects electromagnetically/ or w/e) for example. Touma and index are the main highlights of the regular series.
I like the setting (city) that things take place in. Its a great view. Some people like old timy settings with horses and carages. Some like settings with villages, or small towns, etc. I like settings with technology around. That falls in line with the things i like. I may be talking a lot about what "I" like, but you can judge whether you are like me or not, and whether you will like such a thing.
What really makes this series shine though... is the CHARACTERS. One of my favorite characters of all time is Shirai Kuroko. She is either lesbian or bisexual... or something like that lol. but she is hallarious. Her personality is amazing. The voice actor for her is my favorite voice-to-character match up. I like misaka a lot too, but everybody likes her lol, so ill just say one reason why i like her. She wears shorts under her skirt. so when she is violent and kicks something or wind blows or w/e, you dont see her panties. personally i think its amazingly cute and awesome. Its not only unique, but it shows a certain depth to her personality. The way the characters in this anime play off of each other is great too. Index is somehow not annoying. She is not like the little sister that constantly annoys big brother, and makes you wana say "shut the fuck up you stupid whiney bitch." Of course touma isnt her brother, but hopefully you get my point. No characters in this anime make me want to punch the computer screen. At least not the ones you see often.
For the morals. I suppose it supports the whole "keep your spirits up and do your best" motto that most other animes support, but its not so bad. I hardly notice it, since im absorbed in the characters. This anime puts science and religion together. It doesnt really offend or support either side, so I dont think you should shy away from it if your either atheist or religious (chrisitianity mainly).
My verdict in the end: The story is a bit lacking in explaination, so you dont really "get" what is happening all the time (although there may be some out there that do), BUT!!! since the characters are so wonderful, it makes the story aspect less relevant. an explaination of what i mean: The characters themselves, when going through a crisis in the city, (by the way: there is a lot of action), dont really understand why things are crap all the time either. They just know that perhaps their friend is in trouble, and they are going to go save them... or the city is about to get pulvarized by a giant religious spell, and they need to do w/e to stop it. You get enough of whats going on to get by, and then you watch how the characters deal with the problems and each other along the way. Its an enjoyable ride. The story overall isnt completely incomprehensible. Its just hard to explain I guess.
If anyone cares to add a comment in relation to my points, whether you agree or disagree, or perhaps its not a matter of agreement, but just a different perspective, please leave a comment, so that others can get some various information on this series.
Peace yall :)