We stayed four nights, and had a really great time. It is a a 5 minute walk from Hadrian's Mausoleum, a 10 minute walk to St. Peter's in the Vatican, a 20 minute walk from the Vatican museum, a 30 minute walk from the forum, and a 40 minute walk from the Colosseum, max. In the tourist season, you walk out the door and you are right in the mix of the narrow streets with so many restaurants and cafes.
I would describe the apartment overall as adequate - nothing fancy, but it's got beds, a functional if small kitchen, a shower, and a washing machine, as advertised.
Mostly we had really good communications with the owner, but as we were checking out, we asked what to do with the food waste and plastic we generated over our lengthy stay and did not get a response. Other than that, though, it was fine and everything was as advertised.