I stayed at Marta's apartment for one month and I can only recommend it! The apartment is just like the photos, clean, comfortable, very well decorated and it has all the facilities needed to feel at home! The first day Marta gave me helpful advises regarding my stay in Barcelona and everything that I could find nearby. She was in touch with me during my stay and was always concerned that I was feeling well in the apartment. Its location is great, as at few steps away there are some bakeries, supermarkets, grocery stores and at a 10 min walk there is also a big shopping centre with everything you need. There are some good restaurants nearby and the subway is just 5 minutes walking (Green line, that connects to Ramblas, Plaza de Catalunya, Passeig de Gracia, etc). The neighborhood is realy quiet and, even though the apartment is on the ground-floor, the street is not noisy at all.
I recommend Marta's apartment to everyone that visits Barcelona and looks for a quality apartment, very well located and well equipped.