Dulce's apartment is in the best location in Madrid. It is close to everything, plazas, restaurants, music, theatre, gardens, shopping, activity, transit, etc. you name it and you can get to it by walking 20 mins.
Additionally it you want advice or assistance Dulce is the most helpful host you can find.
We spent 4 days in Madrid and thoroughly enjoyed our trip, partially because Madrid is a great city and partially because of where we stayed.