The apartment is right on the Calle Arenal - near shopping, restaurants, the opera house and palace. It is close to the metro, and an easy walk to the Plaza Mayor. But the street is so loud at night that we were woken up over and over in the front bedroom. Much louder at night than during the day! We closed the metal blinds and used earplugs, but still did not sleep well. The kids, in the back room, were fine.
The apartment was clean, comfortable, and stylish. We had enough room, and everything we needed. The building was safe and had many tourists. The hosts were friendly and helpful, and left us coffee, juice, and local info.
I am sorry I cannot recommend the apartment because of the noise. We would not stay on that street again.