Carla's appartment is the best location by Your stay in Rome. We were 4 adults with 2 children and the appartment is absolutely great. Everything is new, beds are very comfortable. There are two clean and beautiful bathrooms. Location is great, directly in front of the house is Bus and tram stop. Subway is 5min wallking. St. Peter's square is 200meters.
Carla is very very friendly, she helped us with restaurants, sightseeing tips, and also with transport from/to AirPort. And if You'll be nice, You'll get roof surprise ;)