We were super happy with Trastevere. This is a very nice and quiet neighborhood with local restaurants and bars. Also, it was easy and fast to take the tram to central Rome and the bus to the Vatican. Massimo and his son were very nice and easy to communicate with, which felt safe. They both met us at arrival and showed us around. They were also nice enough to arrange for a cab from and to the airport. The locker system for the key worked well.
The apartment was roomy for the 6 of us (but it would have been crowded if all 11 beds had been occupied) and neatly cleaned with comfortable beds. However, the temperature indoors was too low and the tile floors didn't help. Maybe complimentary slippers would be good? Also, there was a shower door missing in one of the two bathrooms. The water temperature in the showers was very uneven, turning cold as soon as somebody else was using the tap/flushing the toilet in either of the bathrooms. (There was also a hole in one of the shower doors, we were told that the last guest broke it, but in a previous review from October a guest says the same thing, that the last guest broke it...).
As a final comment, we were surprised to receive a personal letter from Massimo after our trip claiming that "I would like to inform you that only the maximum score is a positive feedback. Any score less than this means a little more than mediocre appreciation". We don't believe that this is correct at all and not how Airbnb intended the star system. We gave this apartment 4 stars because of size, location and the friendliness of the host. But because of the indoor and water temperature we're more leaning toward 3 stars (which according to Airbnb would still be an Okey grade).