Fantastic location. Piazza Navona is my favorite square in Rom now - I can't get enough of the Bernini fountains. Restaurants around the apartment are all very affordable and the food is as you can expect in Rome: wonderfully delicious.
The apartment is very clean and is cleaned every day, if you like. The bed was firm and thus very comfortable. My electrical plugs from Holland/Germany fit right away into the outlets without any adapter.
There's a cute, pretty well equipped gym just around the corner (Moves) where you can get a day pass for €15.
A Coop supermarket is just on the other side of the Navona square. I counted four ice cream shops in the apartment's street, and there's a nice little Italian pastry shop just around the corner.
The TV has HDMI and my Chromecast played well with the excellent wifi.
Communication was outstanding, and the staff was friendly.