This was a great place to stay and Marco was a very helpful and welcoming host, both leading up to and during our stay. We were just there for one night passing through Rome on our way home after a holiday in Umbria, and it suited our purposes perfectly. It is only five minutes walk from Termini station and but still within easy walking distance of major sights like the Trevi Fountain, Palazzo Barberini and the Spanish Steps (others are further away but still walkable). The guide books say the area around Termini should be avoided and, as Marco confirmed, this is certainly true of the streets to the south of the station, but Via Varsese is to the north and we found it a bustling, pleasant and safe neighbourhood. We ate well in a nice family-run trattoria just minutes from the apartment.
The description of the room and facilities and the previous reviews are spot on. The 'common room' where you can put together your own breakfast (including muesli - yeah!) is actually Marco's own kitchen/diner, which is full of his own art work, homely antique furniture and bits and pieces (even an old vespa scooter). He was there and made us feel very much at home. We weren't out on the terrace much but it is very nice and clearly an asset.
We'd go back and can recommend this B&B.