Great apartment - very comfortable and secure. We stayed with 4 adults and 3 kids under 6yrs old and were fine. Albeit that coming into winter, we were confined indoors and couldnt take advantage of the outdoor balcony. Without an internal lounge room it did make it a bit tight, but we were there to view the city and not the apartment and were out every day of our stay.
Neighborhood is good, with plenty of local quality restaurants to choose from (Il Nipotino del Solitario our fav). Walking at a quick pace gets you into the Trevi Fountain in 20mins - but double that with kids. Colosseum is only 15mins away (with kids). We used the hop-on hop-off bus to get around, which stops just by Basilica of Santa Maria Maggiore.
Only issue was the main door was tricky and required jiggling to get key in properly. We were lock-out once, which was pretty stressful at the time - but one call to Carla and she was able to send someone to help.
Carla's communication was great and she was very helpful in arranging transport from and to the airport for us.