We made a great decision staying at Mauro’s place. The apartment is in the perfect location, incredibly close to the Duomo and shopping, and barely 2 blocks from the subway. The view into the piazza is breathtaking. As others mentioned, you can hear and feel the subway throughout the day but it did seem to stop around 11pm or 12am until 6am. Worth it though for the location and the apartment itself which is beautifully decorated.