We stayed 8 nights in Gianluca's apartment.
Guanluca is a great host. He is always taking care of guests' comfort and doing what is best for them (he was flexible about our arrival and departure, so that we saved a lot of time). He is considerate and reliable (if he says something, he does it and he never forgets).
During our stay, we were not bothered by any noises, it was quiet, so that we could get good rest.
The apartment is perfectly clean. Gianluca checks everything himself so that you can be sure to find everything in working condition and clean. It was also recently renovated, so nearly everything is new and good quality (bed and pillows are comfortable, living room and bedroom are both equiped with air conditioners which are efficient and silent). There is everything you need, not just random stuff, but the host did think about what you might need during your stay you - very thoughtfull.
The apartement is close to Vatican (no transport needed). So you don't have to visit everything in one day, but you can come back on 2 different days in the morning to avoid the lines. As to the other major sites, you can also walk to all of them (that's what we did most of the time), but you should like walking a lot and be good at it. Otherwise the apartment is just next to the San Pietro train station and the bus stop.
If only all airbnbs could be like this...