We had a perfect stay in Massimo's apartment.
The place is spacious, quiet, newly renovated, very clean and fully equipped.
The location is perfect: 50m from the Colosseum, and within walking distance of most attractions. A taxi station is right around the corner, and the metro station is also close, so there's no problem traveling to more distant attractions.
Finally, Massimo was very gracious and helpful.
Highly recommended!