We thoroughly enjoyed our stay at Montse's place and even enjoyed the three flights of stairs to the apartment even though we are 3 ladies approaching 70 years of age. They were not a problem.
The apartment is light, attractive clean and charming overlooking a tree lined street. The location is fantastic. Close to the metro, supermarkets, farmacia, restaurants and the beautiful Sagrada Familiar but far enough away not to be bothered by the crowds.
Montse greeted us warmly and was willing to give assistance where needed. I'd definitely recommend staying there.