Rosario's apartment was a great fit for me and my girlfriend. The place is design for a couple of people and, for our suprise, it was slightly bigger than the image made us believe it was. The position isn't far from city center and metro stations (± 7 minutes on foot) and the neighbourhood, although not the most beautiful of Madrid, is calm.
Concerning Rosario, she is one of the most positive people I have ever seen and she is an incredible host and do everything is needed to help their guests: she even provided us with some breakfast snacks! And the decoration of the place is a plus, certainly!
The boldest drawback is structure of the building: walls seem to be made of paper, so you will listen to the neighbours, always! Also the kitchen is quite small, although functional. And, at last, some piping problem has arisen in the toilet, which we handled but was a little inconvenient.
I must say it was a nice stay and the Rosario's support and care was certainly a plus!