This was our first experience with Airbnb and we were quite pleased with this apartment.
The communication was 100% as they responded promptly and thoroughly to all inquiries. The apartment was well located (walking distance to so many places of interest), very clean, modern and quiet. The building had an elevator which was useful and a good grocery store across the street allowed us to provision for breakfast in the room. Wifi was perfect despite the longest password ever :)
The only minor quibbles were that the apartment can be improved with better pillows and towels. We would certainly stay here again when visiting Barcelona.