We spent 5 nights at Roberta's place and had perfect stay. Comfortable, stylish and very quiet. The location can't be beat -- plenty of great restaurants nearby and it's walking distance to everywhere, with the Colosseo being perhaps the furthest at 20'. The apartment has everything one needs, including a well-equipped kitchen and the bonus of a washer/drier.
The best Airbnb experiences are those that make you feel like you are staying with friends, and that's Navona-Charme. Roberta made us feel at home from the first moment, gave us some great tips off the beaten track and even came by to say "goodbye". So glad we chose to stay here -- can't wait to come back!