There are lots of positives about this apartment, so I'll start with them. It was very clean and comfortable, especially the nice big double bed. The kitchen is small but well stocked with cutlery and cooking equipment and even essentials like salt and oil. The location is good for visiting Vatican City (only 10 mins walk away), which you can even see from the living room windows. It was nice and warm (we stayed in March) and there was plenty of hot water.
However, it was the location that also let this place down for us. It is right next to a busy main road and the traffic is pretty constant all day and throughout the night, including lots of sirens. We also found on the Friday night that there were lots of drunk people making noise for hours in the square outside the apartment. Even with the windows and shutters closed, the noise meant we struggled to sleep.
Claudia initially sent us the wrong address so we walked 40 mins from the train station to an incorrect address and then had another 20 min walk to the correct address. Not a lot of fun on a cold, wet evening.