We had a great stay at Victor & Emma's place and a lot of that was down to Victor & Emma. They let us check-in early and check-out late, which I believe they do for guests whenever possible (and I must add: the official check-in time is better than 99% of other AirBnBs, which often only allow you access to the place you've hired in the mid- to late-afternoon). Communication was as good as you could want. The AC was extremely effective and that was very important as it was incredibly hot and humid in Rome during our stay. The amenities in the flat were all generally of a high standard although the WiFi only just about reached the sleeping area - this could be fixed quite easily I believe.
The flat is super-central - right next to the Roman Forum, in fact - but the location will not suit all travellers as the adjacent streets do not have many amenities and it's certainly not a buzzing area. A 5-minute walk will get you to a busy street with lots of taxis and public transport, and really it's so central that it doesn't take long to get to anywhere in the city with a car. Overall, 5* from us!