We stayed in Carmela's place for two nights in Madrid. She was very flexible with check-in time and the apartment was a great location. We were there during a heat wave, so the upstairs bedroom was too hot for sleeping. There were only two of us, so we could use the main floor bedroom and slept with the door open to allow the air conditioning to reach us. This is a great place to stay for those who will spend a lot of time out enjoying the city or will make use of the patio. The living space is small, so not ideal to spend a lot of time inside, especially with more than two people in your group.
Location was really convenient to local attractions and it was easy to get a taxi at the nearby Plaza del Sol.