Michele's place is perfect in Trastevere. I loved this neighborhood the first time I had a short visit in 2012 and knew I wanted to stay there.
From this apartment, everything you want to see in Rome is a 20-minute walk. I highly recommend the Caremella restaurant around the corner from the apartment. Overall, cozy place, excellent location, I would stay here again.
I will say this: I think staying anywhere in Trastevere comes with a certain level of nightlife you should expect. There was some noise on Friday and Saturday night, but that's to be expected. I think it's worth being close to bars and restaurants. It wasn't bothersome to us.