Our family of four (including our 13 and 11 year old) stayed in Federico's apartment for 6 nights in August.
Before we arrived our communication with Federico was excellent. He was quick to respond to our messages and gave clear information.
The apartment is in a great location - the Colosseum is about 400m from the front door and the Aurelian Wall is at the end if the street! There is a 24 hour supermarket within a couple of blocks, and lots of restaurants/trattorias within roughly the same distance. Bus/tram and Metro stations are all within a short walk too. If you're up to it, Vatican City is only an hour's walk away.
When when we arrived Federico gave us a map of central Rome as well as a map of the local area showing where the supermarket was, ATM, tobacconist for purchasing public transport tickets, etc. The map also had restaurants located on it, but as Federico pointed out, not the tourist restaurants, which was fine by us! We frequented the trattoria on the corner of Via Claudia and Via Annia on several occasions - good value, delicious, traditional Italian food! And friendly staff.
Federico's apartment itself was clean and well presented. It doesn't have a communal loungeroom, which we knew before we booked it, and the kitchen was really too small for the four of us to hang out in. But we didn't mind this - after spending all day sightseeing with each other we didn't mind retiring to our separate bedrooms to relax (there are tv's in both of them although we didn't use them). The shower is on the small side but we managed with it. The kitchen had ample crockery and cutlery and pots and pan. We had planned to do some cooking at night but it was so hot when we were in Rome (between 34-37C) that we couldn't bare the thought of cooking in the heat. Unfortunately Federico's apartment doesn't have air conditioning - just an overhead fan in each of the bedrooms and a pedestal fan which we put in the kitchen. This was probably the only real down side to the apartment - no air conditioning. Although we kept all the windows shut during the day to keep the heat out, it was still pretty warm in the apartment once we got back in the early evening. And there was little point in opening the windows until the sun went down and the heat of the day had subsided. For this reason only, if we were to go to Rome in August again we would probably try to find an apartment with air conditioning. But whether you could find one as conveniently located as Federico's for the same price is another thing.