Firstly, the apartment is exactly as shown in the pictures. The rooms are spacious for two couples and the balcony is as spectacular as one would expect. We had breakfast there every morning. You can see the Sagrada Familia from the corner of the balcony, yet the apartment is not in a tourist neighbourhood, and it has a local feel. There is also a good number of restaurants and super markets within 5 minutes walking distance. The Sagrada Familia is a 7 minute walk, Parc Guell and the old town are 40 minute walks. There are 2 metro stations within 5-7 minutes walking distance, if you wish to get there faster. These metro stations will also take you to/from the airport and the Sants train station.
Rocio is a great host and was there to greet us when we arrived. She provided us with restaurant tips and was very responsive to our inquiries. A bottle of wine and some breakfast food were provided for us when we first arrived. Although not necessary, she also provided us with a paella supper for 4 people and a bottle of wine on our last day. This was a gesture of good will on her part for restricting the use of the balcony one afternoon due to some renovations on the apartment above. As we were out visiting Barcelona, this was not an inconvenience and there were no traces of any work.
All in all, I would highly recommend the apartment and neighbourhood to anyone staying in Barcelona. If you want a local feel that is within walking distance to grocery stores, restaurants, cafés and bars, then this is the place. Lastly, Rocio is a great host with a very pleasant disposition that made our stay very enjoyable.