My one piece of advice, is to book this place!!
1) host is wonderful and extremely accommodating to your needs. He is truly a super host, well-earned! I asked a million questions and he was so accommodating in answering them all!
2) the apartment is extremely close to a metro and makes it so easy to get all over Rome. we bought a 3-day pass and went everywhere so easily. we only used an Uber to get us to the train station, which is very close, on the last day as we had so many bags.
3) Gianluca organized a transfer from the airport for us but it would have been just as easy to take the metro if we had had less luggage. it was a treat though as we were quite tired from jet lag.
4) the apartment itself was very luxurious and so much better than staying in a hotel. I felt GianLuca had thought of every detail. lots of storage space for your items and perfect for four people. the beds were very comfortable. the decorating was pleasing. the kitchen seemed to have every appliance we needed.
5) right next to the apartment complex are several restaurants, grocery shopping and a bakery. at the park across the street is a five-star rated gelato stand that is beyond description. some people said that an apartment near termini would put us in a dicey area. but we were either far enough away or it just wasn't dicey I am not sure which. yes there is the usual people of the street, but that seemed to be true everywhere. we went out at night to several lovely restaurants and felt safe the whole time.