We were with a group of 10 people for 4 nights in the apartment. It has enough beds or sofas and the bathrooms to each bedroom are really great. The roof terrace is a big advantage of the apartment, it's very great. If it is not so good weather to sit outside, it can be a bit tight with 10 people in the lounge.
The advantage of the apartment is the location. It is really only 50m to the nearest metro station and the St. Peter's Basilica or the Vatican Museum are in a walking distance. Unfortunately, the apartment is a little louder than anywhere in a side street, but when you close the windows, it is quiet.
Nikola is a very good host, the apartment was not cleaned yet (the group in front of us was not so clean) and so he invited us for a coffee. The introduction to the apartment was very good and professional, city maps were in the apartment, recommendations for restaurants were also very good and were used by us.