Perfect location for easily visiting The Sagrada Familia and also walking to Parc Guell. Metro station very close.
Apartment was suitable for a family of 5 adults - those with children under 5 might struggle a bit with the stairs as it's 3 floors up. Some street noise, but you'd expect that with this sort of location. However, it was a very good base for exploring Barcelona and we were happy with our choice.
Our hosts Daria and Xavi were able to be flexible with arrival and departure times and were very helpful and quick to respond to email enquiries both before and during our visit.