We LOVED our stay at Frederico's place. We originally were going to stay at a different (cheaper) BnB out by the Colosseum and I am so glad we decided on the one, it was well worth every penny! We were met that the house by one of Federico's colleagues who showed up around the place and gave us contact info if we needed anything while we were there. There was a bottle of wine waiting for us which was a very nice touch.
The bed firm but very comfortable and the shudders blocked out all the street light / noise from the canal. Having the AC at night was a huge plus, but the windows opened up over the river and a lovely courtyard making the day time views spectacular. The bathroom was clean and well appointed, however the hot water heater isn't huge so if two people are staying keep your showers on the shorter side. The space was large enough to be comfortable but not so big you felt like you were wasting money on some huge home you'd only be at for a small percentage of the time.
The location is perfect for walking around the city, we only took a taxi one time while in Rome as we were able to walk to all the historical sites. The neighborhood is full of great restaurants and bars, it was also so easy to find our way back home as we would just follow the river!
I would highly recommend Federico's place to anyone staying in Rome.