We stayed 3 nights at the apartment. It is very comfortable and compact, offered everything we needed. It was very quiet even though it is smack in the middle of all the action of the charming and busy Trastevere streets.
We walked to all the major sights (apart for one time when we took the bus across the river to the Vatican). In the evening you literally walk a few steps to one of many great restaurants.
The owner's daughter was extremely helpful.