My friend and I stayed at Federico's apartment for one week at the end of May.
The apartment is lovely and as pictured in the photos. The living room sofa is a little different but that's just a small detail. We liked that it was very easy to fold it out into a second bed. Overall the apartment is very nice; one of the best features is the balcony.
One thing to note is that the apartment is not close to the city center. We didn't quite realize it was a bit of a trek till we got there - however, for the price it's great value. The number 30 bus (runs as 130 on Sunday) is very close by and takes you into the city center in about 15-20 minutes.
There are some nice restaurants and amenities nearby: there's a nice coffee shop around the corner where we enjoyed a cappuccino and croissant every morning. There are a couple of nice restaurants within 5 to 10 minutes walking distance. The pizza at La Rosa Rosso is excellent, perhaps the best we had in Rome. There's also a small grocery store about 5 to 10 minutes away. And there's a taxi stand near by which is convenient.
Federico is a good host and he's helpful and responsive.