We stayed in the flat for 4 nights and we really enjoyed it. The place is small, but has everything you need. The location is perfect for exploring all parts of Rome, being about 20-25 minutes walking distance from most attractions! Campo de' Fiori is less than 2 minutes away, Piazza Navona is about 5 minutes, and so is the Pantheon.
There is a bakery just round the corner which is amazing, we had breakfast there every day and they were extremely friendly.
Communication and check-in were perfect, and we had no issue at all during our stay. Giorgio even allowed us to keep the keys for the flat a little bit longer because our flight wasn't until the evening, which was very nice of him!
Internet connection works really well in the flat, and there is air conditioning in case it gets too warm.
I would strongly recommend staying here if you need a central place to stay when visiting Rome - you can walk everywhere and enjoy the whole of Rome!