Marta is a wonderful host. She is VERY responsive and attentive prior to and during the stay. The apartment is located in a very central part of Madrid and within a block of one of the main Metro lines (Urgell station).
I should point out that this apartment is not a full-time Airbnb. You are staying in someone's apartment while they are not there. So, for some travelers, it may feel a bit cluttered. Otherwise, everything was fantastic.