Amazing place for staying in Barcelona! Montserrat and Narcis are lovely and offer a modern apartment, very clean and well equipped with everything you will need. We stayed in 6 people for 7 nights and we didn’t have any problem, I would recommend this place to everyone!
The only downside I would say is that the place is not so close to the main tourist attractions as you probably will need a 30-40 minutes walk or get a subway, but the good point is that the apartment really is very close to the Sagrada Familia and its subway stop