Joaquin's apartment is perfectly located as it is just one block from Urgell metro station, which is also one of the stops that the airport bus stops near. The return airport bus stop is one street over (Carter de Sepulveda), between Carrer del Comte Urgell and Carrer del Comte Borrell. It is close enough to the main attractions that you can walk there or take the metro, but far enough away that you avoid the crowds of tourists.
I would say that this is one of the best equipped apartments I've visited on Airbnb. They had a kettle, toaster, microwave, stove, oven and washing machine in the kitchen. There were plenty of plates, glasses, mugs and cutlery too. There are also plenty of places to eat nearby.
The place was very quiet apart from the occasional sounds from the neighbours but I never had any issues getting to sleep.
I enjoyed my time in Barcelona and hope to return again soon.