Paolo's place was overall great. We were four adults and one child, and the sleeping arrangements were fine (one double and one single bed in each of the two bedrooms, two full bathrooms). The place is very well located, especially for St Peter's and Castel Sant'Angelo, and Piazza Navona and the old city centre is only a short and lovely walk away. The apartment itself was clean, everything basically needful was in place, and Paolo's communication was superbly prompt and informative.
That said, the visit did not start well. The driver Paolo arranged was not there to pick us up at the airport, and then the agent was not present at the door (Paolo and his partner are evidently in charge of a small empire of apartments, which are run by an agency). To make things worse, the doorbell was not marked (contrary to what we had been told), so we could not ring. The agent soon arrived, but even after I had confirmed with Paolo which doorbell it was, it turned out it didn't work. This was disastrous for our friends, who arrived early the next morning after a trans-atlantic flight and were stranded at the door, unable to ring it or to call us, for half an hour in the rain. Not great.
As for the apartment, it was lovely, light-filled, and quiet, though there are only two hobs so the kitchen is not really sufficient for cooking large meals, and the coffee is in pods, which both taste bad and are horrible for the environment.
Again, overall the place was great; we recommend it, especially for short stays and if you're happy to eat out.