This place is amazing. We were just there for 2 full months, and this flat is awesome. It's quiet at night, on a quiet street, but less than 50 meters away is a lot of awesome night life.
The beds are super comfortable, and the showers are equally great. I don't have anything but good things to say about Matias' place.
If you're going to be in Madrid, and want to stay in a super cool neighborhood that's convenient, and safe, I totally recommend this flat.
By the end of our time the flat really felt like home to us, we were very sad to leave Madrid, but now we know where to stay when we go back!