I spent only one night in Madrid for transfer and stayed that night at Marifé's place. The connection to the airport is convenient (about 10-15 minutes in taxi from T4, 22 Euro, about 20-25 minutes to T4 in metro, the nearest metro stop being Hortaleza). The place was very clean and communication with Marifé fast. I arrived in Madrid late in the evening and she waited for me although she had to work early the next morning. Thank you, Marifé!