Overall, an amazing place to stay. The Airbnb is *gorgeous* and quite modern. Please keep in mind that, although this only 2 flights of stairs up, each flight is about 20 steps. This was no problem for us, but could be a challenge for some folks!
Trastevere is a perfect place to be when visiting Rome. We ate within the neighborhood for almost all of our meals, and could walk to all the major sights. As others noted, the street is very loud -- screaming and signing were heard clearly through 4 o'clock in the morning. We were generally okay with this as we live in a city, but it can be disruptive for early mornings, etc.
We had a hard time finding the dishes, glasses, and silverware: they're in the living room in the cabinet the TV is sitting on. We also were a bit disappointed with the pillows on the bed -- there were only 2 and they were very flat. My partner and I both experienced neck pain. But, again, this might've just been us!
Overall, Carlotta was a great host and provided us with local recommendations. She was super responsive and willing to help. I'd recommend anyone stay here if they're okay with the noise -- perhaps just bring a pillow or 2!