Great flat - incredibly - just ten feet from the subway entrance.
If you are coming from Termini station, don't even try to walk there, it's too far. Take the subway and get off at Piazza Vittorio. Exit to the left of the turn aisle, and keep walking staying to the left. At the exit you'll see the door right in front of you.
It does get a tad noisy, with the traffic, but it's on the 5th floor, and with the windows closed, it's ok.
The fan / AC is sort of weak, but these are truly the only negatives.
It theoretically could accommodate up to 6 people, but I wouldn't push it, because there is only one small bathroom.
It is perfect though for a couple, and we enjoyed our stay.