Really lovely apartment, it's decorated nicely and very comfortable, with plenty of space to hang clothes in the wardrobe, etc. I walked to the Termini in about 10 minutes (there is an entrance is about halfway up) and the Colosseum around 20 mins. The local restaurant she recommended was also very nice and filled with locals. The security of the building is good and the door has a secure bolt on it.
The only downside for me was the noise in the evening, I am a light sleeper so the traffic and sound of the trams passing by made it difficult to sleep the first night. So bring ear plugs if you're a light sleeper!