Hi alex,
i actually live very close to plaza de la luna. And for more than ten years that i lived there, there are no experiences of my own or other people that i know, indicating that it is a dangerous place. I don't think it is more dangerous than manhattan for example.
Although, yes there is some prostitution in the area, but i think it's more unpleasant for some people than dangerous.

Let me know if you need more information.

(i also work in computers)

 

Hey, i graduated in computer science and i will come to madrid in september, if you are looking for work partner we can discuss it
my msn: marcellomarchese gmail com
marcello