Out of all the European accommodations that I've experienced, staying at Aga's was by far the most pleasant experience. She went above and beyond what any guest would have expected from their host. First, she sent us an email detailing all the best places to visit in Barcelona (both food and attractions). The email also contained very accurate directions on how to get to her place from the airport. Second, she waited patiently for us in the apartment until we got there despite us being half an hour late for check-in because we were figuring out train timings. When we got there, she welcomed us warmly and showed us around the place while explaining a little about the events that were taking place in the area. She even sat us down and gave us a map complete with instructions on how to get from place to place. Third, she let us leave our belongings in the apartment until 9pm although we were already supposed to check out in the morning. She just set a time and acceded to our request without the slightest grumble!
As for the apartment itself, it was fully furnished with two bathrooms and comfortable beds. It even came with a washing machine and air-conditioning. The apartment was smack right in the middle of all the tourist attractions and most places were within walking distance.
All in all, I would recommend staying with Aga if you want to have the best possible experience in the city of Barcelona.