Pros
Excellent location, in the heart of Madrid, with tonnes of transport options.
Clean flat with good amenities.
Cons.
Even after explaining multiple times (well ahead of our stay) the exact arrival time (and contact information) of my parents, the host refused to meet them at their arrival time. So they were left waiting on the street for one hour, absolutely disgusting attitude from the host. When I was made aware of the situation, I rang the host to ask them to meet my parents and let them into the apartment, this request was refused. These hosts will meet you when it suits them, not when you need, this might be because they don't have a reception, don't have anyone from the host company nearby or they simply don't care (as in my case).