Yes, I finished watching Toaru Kagaku no Railgun S(for sisters and also second season), and it was glorious. For all intents and purposes, it's better than the first season. Better story, better action, better music, better character development, and also better animation. It was this show that allowed the Railgun series to become my #1 anime. Allow me to tell you why!
The story goes like this: During the second half of Misaka Mikoto(our Main Character)'s summer vacation, she gets dragged into yet another mystery. Judgement has been getting tons of reports of cash cards in envelopes lying around in alleyways. Mikoto doesn't think much of this, but when she overhears some punks talking about the culprit, she follows them to said culprit's hideout. The culprit, a very odd girl in a lab coat, mentions something about her being "The Original"(she's a pepper!), which sparks(geddit) her interest. It causes her to recall strange rumors she's heard about "Clones of a Level 5", and more specifically, that those clones are of her. As you should have learned from the first season: All rumors in Academy City are true in some way. Mikoto is caught up in this strange mystery, and will enter into a fight for her life, and for the lives of those known only as "The Sisters".
The story is great because of just how deeply it effects the heroine, and how it effects those around her. It is a very sad tale, filled with regret, anger, and despair. It's very unlike the first season on the surface, being much darker for the first arc. Underneath, however, it is eerily similar(in a good way). A good thing to remember is both the mindset of Kiyama Harumi, and Therestina Lifeline, as both of those come into play. The first is subtle(less so if you read the manga), but the second is directly addressed in the second arc. It deals with a little girl named Febri and how she ties into the first arc, and it ends with a fantastic finale. While it has it's problems and isn't as good when compared to the first, it's still pretty good. Even with things such as the poor characterization of the antagonists in it and the unnecessary appearance certain people. The plot as a whole is also very well paced, and has very interesting themes. It has plenty of character moments that are both heartwarming and interesting, so they're just enjoyable to see. Not to mention, if you haven't seen the first season you can still get into this one. Everything is explained in a non-overbearing way, and the first episode reintroduces the characters and setting. It's something that is highly compelling, somewhat thought-provoking at times, and overall very good. The only real problem I have is that it feels less cohesive than the first season, as in the first it all felt like one whole story arc told semi-episodically, but in this there is a clear divide between arcs especially because both are each one continuous plotline. It does make up for this however in pretty much all other areas. Also, the last episode may require a bit more suspension of disbelief than normal, which might be a problem for many.
The characters are the same as before, with some new ones showing up(most of which take antagonistic roles). However, there is something different about them this time. I mentioned that, while the character development didn't amount to all that much last season, the characters and were still good and highly endearing. Railgun was good in regards to character building, by showing things like backstory, character interactions, and simple small things that helped give you more info on their character. However, I think that Railgun S is much better, having more and better character building moments. Mikoto has a much bigger and longer character arc as well. Learning more about a certain experiment and having some pretty shitty things happen to her, she begins a downward spiral. However, when the second arc rolls around, she starts to feel much better and reflects on what she's learned, allowing her to become a person willing to accept other people's help, and accept that they're willing to help even if it's dangerous. It's really good. A certain someone(or should I say, someones?) also changes, becoming able to value their life, and the chain reaction for the antagonist's change into the character he is now in Index starts here. In addition, there are also scenes that focus on new aspects of characters, such as a side of Kuroko one doesn't often see, and more of Uiharu's surprisingly stalwart side we got to see at the end of the first season. There is a good deal of character growth in this season, and it's wonderful. I don't think anyone goes away without learning a lesson. Except for Touma. Touma cannot change, learn, or grow. Touma is a constant. Anywho, Character = Good. The only problems I have with the characters are the things I mentioned in the plot evaluation. The main antagonist and his cohorts in the second arc were not focused on enough to be all that compelling and we are expected to either despise or sympathize with them as usual, but I really did neither. Again, however, it makes up for this by developing and/or giving character growth to the other characters.
Animation! Yes, the animation is a bunch better. The backgrounds are highly detailed and help set the tone for scenes. They're almost part of the story itself. The character animations are also a lot better, with more dynamic...ness? to them. Action animation has also taken a step up, with some very lovely and tense fights(feat. Explosions), with the last episode being the best. Animation isn't the best I've ever seen or anything, but it's pretty damn good. And hell, the overall quality of the art is just great, probably one of the most pleasing to look at of 2013.
Music too, is a lot better. Where as few pieces stuck out in Railgun, plenty of pieces stick out in S. In fact, a good amount of the story's impact can be attributed to the music. It's very good, with a few more melancholic pieces, and to contrast some good electronic beats. The music that plays during the "Bridge Scene" is especially good, and way better than the song in Index's version of that scene. The OPs and EDs are also great, with the second OP, Eternal Reality, being my favourite so far. EDIT: As it turns out, the first season had plenty of good tracks. In fact, some of the notable ones in S are from the first.
Overall: Railgun S is a great anime. It brings Railgun up from a simple popcorn anime(to be totally fair, that is what the first season was), to something that is trying to be a good character drama, and is very much succeeding. I really hope we get a third season, but if not, this is certainly a good one to stop with. It has both a darker tone, and yet an even more hopeful attitude than the first season(though, that won't be apparent until after the first arc ends), and really does feel just plain good. It fully cemented the Railgun series as one of my favorite Sci-fi series, and Misaka Mikoto as one of my favorite characters. Even if that second arc is kinda questionable. I really can't stress enough how good this is, and how much I love it. Here's hoping for another season! If what I've said sounds good to you, please do watch this show. If you haven't seen the first season, I'd also recommend watching that as well, but it's not 100% necessary.
So, without further ado, I award Toaru Kagaku no Railgun S: 5/5 clones doing the wave.
If you don't get that reference.
EDIT: I also wanted to mention this anime's use of "Cinematography". During particularly intense scenes, the "camera" will wobble a tad(I noticed this first during the scene where Mikoto attempts to fire her Railgun at a certain someone). There is also a scene in which quite fitting music plays and the "camera" moves in a sweeping motion from the perspective of Mikoto and the person she is looking at. It's a fantastically directed scene I think. Also, during the serious parts of the first arc, mostly those where Mikoto is alone, the "shot" is close and constrained. The color of these scenes is also darker. During the lighter scenes, mostly those in the second arc, the "shot" is farther out and more relaxed, and the color is lighter. This makes a great contrast, and works great. There are plenty of other really great "shots". Overall, what I'm saying is that it's very well directed. There need to be more anime that take advantage of being anime for great pseudo-cinematography like this. I also should mention the voice-acting in this is fantastic. Mostly Satou Rina's performance which makes it feel like she really was shook up about it all. Basically, while you may argue the quality of the story(I think it's great), you shouldn't argue the quality of the execution. It's really damn moving and emotional. Anime is of course a visual medium, and I think Railgun S is very visually appealing. More so then the first season, way more than Index, and shit ton more than JC Staff's more lazy works(you know the ones I'm talking about).
BTW, I say it in quotations because it can't really be called cinematography or camera work as there is no camera or shots. It's all animated. But that doesn't mean you can't emulate it.