The room is very cool with a lot of light and a nice view from the window. The apartment is nice as well, very charming and nicely arranged. The area around (Malasana) is really cool and full of bars and restaurants, but from the room you do not hear any noise and you sleep really well.
I spent more than 20 days there and I can say as well that both Javier and his flat mate are really nice and the time spent in the apartment has always been enjoyable.
Small remarks: if you have a big luggage, the room might be a bit small for you. Fourth floor, no elevator, so not good for people that do not like to climb stairs :)