I recommend Amira's apartment. First, you will receive a warm welcome from her. Amira takes the time to go around the apartment with you. She will provide you a map of the city with plenty of recommendations on where to go, ways to get around. She remains available if she is needed. The apartment is very well located, 10 minutes walk from the Sagrad Familia, 5 minutes from the metro station, there are plenty of small local markets around. The apartment is at the 3rd floor, so it will keep you in shape everyday, and it's quiet in the building. I'm sure you will enjoy your stay there.