Mirella's apartment was perfect for our holiday, we spent there 4 days. The location is really good, 15 minutes walk from Sagrada Familia and 4 metro station from the center. The metro station is close to the apartment. There is a supermarket close to the flat and we have found really nice places for breakfast.
The apartment is well-equipped with nice furniture and good structured. We had problem only with the wifi, sometimes it disconnected and it was relative cold in the flat (end of March).
But overall it is a really good apartment, I can recommend to everyone. And Mirella was a really nice and helpfull host. :)