I am from Vietnam and I stay at Maria's for 2 months to learn Spanish.
Maria is so wonderful. She is very warm and caring. She makes me feel immediately at home. She is also very helpful with all sort of information. She is very responsive and communicates clearly. She also goes beyond above to help me practicing Spanish and learning more about Spanish culture.
The apartment is exactly as described. It's located on the 3rd floor of an old Spanish style building with no elevator. For me, it is all right because i don't have much stuff and I really enjoy a bit of exercise from climbing the stairs. The apartment is clean and homy. The location is very nice, walking distance from everything: retino park (5 mins), Sol (30 mins), goya metro station (10m), shopping mall - el corte ingles ( 200m across the street), different varieties of markets ( within a block from eco, carefare, fruits, etc.). There is no time-restriction for lock-out.
Overall, I highly recommend to anyone who wants to have a really good experience in Madrid.