My family and I stayed in the apartment for 3 nights with 6 adults.
The location is perfect, central - close to the Quirinale, Trevi Fountain, Barberini metro... If you like to walk, the location is especially perfect - you can reach the Colosseum, the Pantheon, etc all by foot.
It was a bit tight with all grown folks. I think 4-5 adults would have been more comfortable. The toughest thing is having just the one bathroom. Funnily enough, we thought the sofabed in the living room was more comfortable than the queen bed mattress in the main bedroom. Also, despite facing onto the street, the sofabed in the living room wasn't noisy at night, despite what you'd expect. The apartment was superbly tidy, although I would bring slippers for extra comfort and cleanliness: since the floor is tile, it naturally carries dirt more than wood, and can be a bit cold. The apartment is a bit quirky, so pay close attention to the house rules when you check in. Otherwise you might find yourself without hot water, a working fridge, lights, or elevator because you pressed a wrong switch or turned the wrong knob lol. In particular, PSA for folks who are used to central air: the thermostat in the hallway is *not* for the AC, it's to control the hot water temperature.
Finally, Bruna is an amazing host. She truly embodies the reason why someone would want to book Airbnb over a hotel. She is very responsive and has a slew of recommendations for restaurants and tours. Some delicious spots she sent us included La Tenuta di Rocca Bruna in Tivoli, Egg near Vatican City, and Birreria Antica Peroni (open late) near the apartment. (I also recommend Gelato di San Crispino which is also by the apartment and is mentioned in Eat Pray Love). She also connected us with a tour operator who provided us with an excellent tour of the Colosseum and the Underground by night. He also gave us a great discount since we had 7 people.
Overall it was my first visit to Rome and we had a great time. Thanks Bruna!