This was a wonderful Airbnb experience. Sergio was warm, friendly, and super respectful; he met me at the apartment, which was even better than the pictures, and graciously helped me settle in. The neighborhood was lively but quiet (also, for nerds like me: Lavapiés is an important site in Spanish cultural history, especially the history of madrileño class politics); it's full of opportunities for good food and offers a number of easy transport options.