We had a great time in this apartment and would really recommend it. From the Atocha train station you can walk easily to the apartment, which is located in a very nice and vivid area of the inner city. During our four days we seldomly used the metro because you can reach all the interesting spots (like e.g. Retiro park, Royal Palace, or Chuecha district) by foot.
Next to it you can find restaurants, mini markets and shops. So even if you arrive earlier than check-in time you can find places to go. However, Paula and her boyfriend were very welcoming and helpful, we could store the lugagge before as well as after our stay in their appartment.
The apartment itself is very comfortable, with a nice interior, kitchen and bath. We also got a tasty fresh bread at our arrival, and they offered tea, milk, coffee and cereals too. Paula and her family live in the same building, and are available if there is need to. Altogether, it was a wonderful time and we would certainly stay there again.