Great location, close to Piazza Testaccio but far enough that there wasn't a lot of noise at night. Walkable distance away from most sights but not quite as touristy as Trastevere for example.
As for the apartment, it was ok. Many things, including bed sheets, mattress and kitchen wares are worn and old, but I suppose that's reflected in the price.
Monica always responded quickly to questions and checkin went smoothly. No complaints there, other than maybe the 10am checkout time which is a bit early.