I booked one of Federico's apartments (Apartment A) in Trastevere for my friends. The location was perfect, since it's very close to the Tram 8 stop, right across from the Porta Portese Sunday Market, and only 2 stops away (on either side) from Trastevere station or the heart of the Trastevere tourist area.
The booking process was very smooth, with Federico or his staff replying promptly to everything I asked, and when I went to see the place, his staff was waiting to receive me and show me around.
The apartments are set up very well, like a hotel! The only thing my friends were a bit concerned about was the steep incline to reach the building, but that's not a flaw - just something to be aware of.
All in all, it was a great experience and below is a note from my friends:
"The flat was excellent in all aspects and beyond our expectations. Travelling with kids, we are always weary - but Federico's team put us at ease. Katherine was very attentive in every aspect of hand-over. Zubeida was meticulous in her cleaning. They both went above and beyond their duty and helped with tidbits. The place was so excellent we booked it again!"