The best service you can possibly find in Airbnb, they have other places aside from this one and they're professionals.
This place is huge, sleeps 6 easily, with two bathrooms. The apartment was recently painted, it also has a heater that works really well and the mattresses are very comfortable. The kitchen has the basic things you'll need to just eat or even cook as we did ourselves.
The locations couldn't be better, 2 blocks from Sagrada Familia, 2 markets around the corner, metro stations no more than 5 minutes walking.
There is a street, in one of the Sagrada Familia's corner that has many restaurants and bars.
The guys who manage the apartment provide a basic supply of grocery things as a welcome package that is nice super useful, they also give tips about where to eat and to go in the city.
No doubt I would stay here when I go back to Barcelona.