This place is, in a word, lovely. It is well furnished, clean and spacious. With two mid size bathrooms and two bedrooms (plus the sofa-bed) there is enough room for quite a few people to comfortably stay. It is also nice to have the convenience of a kitchen and a washing machine. The view from the window is also great and, whilst I did worry a bit when I first arrived, pretty much all of the noise of traffic is blocked out by the windows. My only issue would be with the air-conditioning (which was a bit temperamental at times).
The location is not too bad at all. It's about a 15-20 minute walk to most tourist attractions and good restaurants (but a walk through Rome is rarely a chore) and it's close to the station, Convento dei Frati Cappuccini, National Gallery of Ancient Art and Chiesa di Santa Maria della Vittoria (all of which are well worth a visit).