Maria's flat is awesome!! Campo de Fiori is a great location, especially if you plan to hit the "lesser traveled" parts of town like Testaccio, in addition to the Vatican, Coliseum, etc. We walked everywhere without any issues, and really liked coming back to a lively town square area in the evenings. Side note, the windows are amazing at this place, so even if there are tons of people out in the square, you can close the patio doors and it's silent. The patio is also very unique and a huge plus for an Airbnb in Rome. You'll pay double this price or more at a hotel. We loved our stay here, Maria was great, and she even arranged a driver to take us to the airport when we left, which was an added convenience. Fantastic!