We stayed at Rocco's place for 1 night, and it was great! It was conveniently located near Termini station and within walking distance to the Colosseum.
Rocco was very kind to let us drop off our bags early because we arrived before check-in time. He also gave wonderful restaurant recommendations (Zizzi pizza nearby is fantastic!).
Since the apartment is on the ground level, it is possible to hear street noise and passersby, but it was generally quiet while we were there. I didn't have any trouble sleeping, and Rocco provided earplugs just in case. The bed was super comfortable! He also generously left drinks and food for breakfast (cereal, nutella, croissants, etc.). The hot water in the shower was a bit inconsistent, but it stayed hot long enough to shower.
I would recommend Rocco's place if you are looking for a great AirBnB close to Termini!