The main advantage of the place is its location in the very heart of the city. It's literally one building away from Piazza Navona, and at the same time the apartment is very quiet thanks to modern soundproof windows.
On the other hand, 5 flights of stairs, and a very narrow (less than 2 feet wide) apartment door can be a challenge for those who have heavy and/or bulky luggage or are not very strong physically.