It was great staying at Alejandro's place! Extremely central to Puerta del Sol and shopping and yet, because it's on the 4th floor, and our room didn't face the street, it was very quiet.
He was a knowledgeable, friendly host and the room was extremely comfortable. The decoration was absolutely lovely (one of the perks about staying at an Air BnB).
Be sure to give it 10 minutes after one person showers to use the shower again--it takes a bit for the water heater, but it wasn't a pain for us.