We came to Barcelona to attend a conference at the business school. Pau's apartment was an ideal location for the metro stations, both to the business school and to the city center and beaches. The apartment was beautiful, spacious and very comfortable! It's in a fantastic neighborhood with lots of shops and restaurants (for perfect cappuccinos, at any hour, try Sandwichez, just around the corner). Perfect if you are looking to stay somewhere out of the normal tourist districts. There are lots of fun bars and fantastic tapas places to be discovered in Gracia. Also easy to walk to Park Guell from here.
Pau was very helpful with local recommendations and traveling logistics. He was the ideal host (and his english is perfect!).
I'd recommend taking a taxi from the airport, especially if there are three of you and/or you have a lot of bags.
The air conditioner and washing machine were also much appreciated!!!!