We really enjoyed our stay here. Sergio was very responsive and accommodated our delayed arrival (which ended up being very late at night). The apartment was extremely clean and very comfortable, and the room we stayed in had a nice balcony with an awesome view of St. Peter's. In terms of the location, it was easy to use the bus system (one is literally outside the door and there are several others just a few minutes walk from the apartment) to get around during the day, and it was particularly convenient to get to the Vatican and St. Peter's Basilica from the apartment. At night you should be prepared to take a taxi home if you are coming from other parts of town as the busses run less frequently at night (but this is true for getting around all over Rome at night). Would definitely recommend staying here!