Me and my friends (3 persons in all) spent a weekend in Barcelona and I have to say that Alex' appartment made the trip perfect! It is located at 5 minutes walking distance from Sagrada Familia in a charming house with Elevator! You couldn't wish for more - a spacious appartment, very clean and lovingly equipped. A big bathroom with a wonderful shower and cozy big towels. The beds are big and very comfortable (after a day of walking through town that's very important! :-) ) And most of all, the place is really quite and with the shutters closed you have a heavenly sleep. I'd say you can stay there with 4 people who know each other well (not so many doors...) very comfortably. We didn't use the kitchen but it had everything you might need for cooking.
You find a big folder with all kinds of tipps for your stay and Alex himself is extremly helpful should you have any questions. Thank you Alex, for making our Barcelona experience so extra good!