I couldn't recommend more highly Maria as a host. She looks out for you like a mother. When I arrived I had no idea where to start with Buenos Aires but she quickly orientated me by giving me tips for the city and maps. Her home is beautiful and quirky and clean. Make sure you are able to carry your luggage up about 10 steps. You will also be sharing a bathroom. Palermo is definitely where you want to stay... its upmarket and safe and close to lots of restaurants, cafe and shops, and about 10 min walk to the nearest subway.