Just started watching this today on a whim and it was really nothing like I expected it to be. Which isn't necessarily a bad thing. To Aru Majutsu no Index started out as a series of light novels by Kazuma Kamachi and was made into an anime last year and as of now is up to episode 24. I had accumulated about 20 episodes and figured I should finally start watching this series. Kamijou Touma has horrible luck, and he lives in a "school city" full of students, where science is extremely advanced and where people have esper powers. He doesn't believe in magic, however, until he stumbles upon a girl that claims to be the embodiment of 103,000 volumes of magic locked away by the church. And that's where I begin to have problems. The esper x science element seemed really cool, and then they have to throw some weird religious mumbo-jumbo in there. And I know that it's majorly thematic of both the light novels and the anime. It seems fairly action-packed so far, and I may continue to give it a fair shot, but I think ultimately the religious themes will probably end up putting me off of this by episode 10 or so.
Anyway, the series hits the ground running, not really explaining what's going on right away, but it kind of integrates what's going on into the story without being blatant about it. The only real complaint I had was that the relationship between Touma and Misaka seems really nebulous. At the beginning of episode 1, it seems as though he doesn't even know her, and then toward the middle, into episode 2 they seem like old rivals or something. It's revealed in episode one that Index is running from someone and that she needs to keep moving, and then at the end of ep 1 Touma finds her passed out and bloody on the ground. Enter our antagonist. Ep 2 involves Touma and generic-ish fire-wielding badguy Stiyl-Magnus exchanging words and hard glances, Touma getting a grip on his power and ultimately having to have his teacher (who is a total piece of lolicon fanservice) save Index due to his right hand being the negator of all magic.
All-in-all I think it's a bit of a clusterfuck so far. You have lots and lots of terms thrown at you in the first two eps, and stuff doesn't of necessity make that much sense, or it seems tacked on (or perhaps like it should've been introduced later). You have humans talking about advanced science, esper powers, then magic. The main character's power is negating all of this with his right hand which some of the time it seems like he's known for years, other times it seems like someone just introduced him to it. Some sort of "magic naming system" is mentioned with Index and Magnus that seems like an old aol screenname thing (Magnus being called Fortis931). Like I said above, unless the concentration aims away from the whole religion thing and some clarity comes to the story I'll probably stop watching this series. Which is a shame because I really liked nearly every character except the generic badguy, so far.