I was in Marta's house for about 1 month. It is in the great location in barcelona, shops, pharmacy and supermarket (Dia or BonArea) are nearby and around 5 minutes walking.
The house is very close to metro line 1 as well.
Marta is a very nice host too. She responded and supported all the time. Even when I needed a new microwace, although it was sunday but she brought me one in the same day.
Just behind the house is a school which they make some noises during the day but for me was not a problem at all.
In General I am very happy and recommend it.