I stayed in Walter and Cecilia's apartment for four weeks, and it was absolutely perfect for me. The location is very good, five minutes by foot from the nearest metro station. From there you can travel to the historic centre in only five or ten minutes, or to the Vatican in less than fifteen. The apartment itself is brilliant, quite big for one person and very comfortable even for a long stay. Walter and Cecilia themselves are very friendly and helpful. I had almost no problems during my stay, but any time I messaged them they responded very quickly. Check-in was very straightforward. I would happily have stayed longer and would definitely stay here again. Highly recommend. :)