Very well situated for sightseeing (20min walk to the Prado Museum, 10min walk to Plaza Mayor), well equipped, beautiful and clean apartment: we had a great time staying at Sylwia's place. Sylwia was easy to communicate with and very welcoming. The beds were comfortable, the kitchen well equipped with appliances and the shower very roomy. Plenty of storage and power outlets, good working wifi.
From the airport it is easiest to take bus 200 and then metro 5 to La Latina station, but if needed you can ask Sylwia about her friend who will collect you from the airport for a reasonable fee.
We were there for an exceptionally cold and rainy week in April, but the apartment was comfortable and roomy. Would very much recommend!