The apartment is small and cozy, very suitable for couples. It is somewhat smaller than the pictures make it seem, but as long as it is just one or two of you, it is very comfortable.
The location is good, but we advise you to figure out public transportation beforehand to save some time if you prefer to use it rather than walking. Rather than being in the center of Trastevere where all the bars and restaurants are (Santa Maria Square), the apartment is more in the industrial area of Trastevere. It is right by the river, though, and if you are up for an hour or so walk each way, you can get into the center of Rome easily with a nice stroll along the Tiber.
Vincenzo is a terrific host, there was great communication between us, he left us a very detailed notebook with tips and places to see in Rome and later he even texted us a detailed list of good restaurants and caffés. He also was very understanding of our flight delay and happily met us at the apartment at midnight, which was a huge relief for us.
If you're a young couple going to Rome, I would highly reccomend this apartment.