We stayed in Alex's house for 4 days. He was really kind and helpful.
The house in very nice and with everything you need for your stay. The location is great. The metro is very close (about 2 minutes) and some sights can be reached easily on foot, like: Arc de triomf, Plaça de Catalunya (about 10 minutes), la Sagrada Familia (about 15 minutes)...
Highly recommended if you are going to visit Barcelona.