We stayed for five days in the apartment and it was perfect! It's located in a beautiful quartiere named 'Coppede'. You will be amazed when entering: you will find very inspiring houses and a lovely fontein. From Termini station it's only 10-15min by bus. The apartment is on 2 min walking distance from Buenos Aires plaza which offers a lot of good facilities (coffeebars, supermarket, restaurants and shops, bus and tram). The apartment is runned by a family and our host Alessandro was really helpfull. When he discovered we like to dance tango, he made a list with the locations and helped us with the public transport. This was a warm welcome!
What we liked the most about the apartment was the little balcony with the beautiful view (you can see the houses desiged by Coppede!). The apartment self is brand new. It has two bedrooms, a livingroom with kitchen and airco. The kitchen is well equiped and there is enough space for four persons. If I will go back to Rome, I definitely go back to this place!
One tip: if you're planning to visit galleria Borgese (the park is on walking distance), book the tickets in advance. Unfortunately we couldn't visit the museum, it was fully booked for the whole week!