The studio apartment is nice, compact an has everything you need. Catharine also provided a welcome breakfast and a bottle of wine. There are several apartments rented like this one around and overall they are well prepared for hosting guests.
It is located next to the lightrail station. And if the balcony door is open you can here trains passing by and station's announcements. The same as the noises inside the building - heating, pipes, neighbors, doors shutting. But from my experience it was quite common for many places in Italy where I stayed.
It is connected with the most touristic part of the city with a direct bus 64 (I think it doesn't operate during night) and close to Vatican if you are interested. But generally all the activities are away from you. So whatever we wanted to do (restaurants, bars, walking in nice areas) was half an hour of walking or a bus-ride away.