My colleague and I booked Roberto's apartment at the last minute after our flight home was canceled using Airbnb's instant booking feature. Roberto was quick to send us information about how to check in.
Unfortunately, we didn't have a great experience after that. The flat directly overlooks a favela, which we could hear as soon as we opened the door. It may have been louder than usual since we arrived on Brazil's Independence Day, but for the sake of transparency: we heard loud music, people shouting, dogs barking, roosters crowing, and the occasional firework going off.
That aside, the flat appears as promised (although the second bathroom was more of a W.C. with a shower head than a full bath) and the building had helpful security/doormen. And Ipanema is a wonderful little neighborhood. This flat may be best for travelers on a budget who just need a place to lay their heads before setting off for the day.