Candid review:
Inca the host was really helpful and communicative.
The location is great - about a half hour walk to vatican city, pantheon/spanish steps/trevi fountain, and to the colosseum. The food in this area (Trastevere) is also fantastic, and you have dozens of options to choose from within 10 minutes.
Check in was totally fine. You need to arrange a time before hand to meet for check in, since they need to let you in the first time. It is the top floor apartment of 5 (maybe 6?) floors I think, and there are no elevators, just the stairs. The stairs aren't air conditioned.
The apartment: similar to an older, remodeled small New York apartment. Has everything you need, everything a little on the petite side. Small bathtub and a little cramped for showering with the window being part of the shower wall, but totally manageable. A little hard to keep water from getting onto the floor when you shower. A mini fridge and small washer in the kitchen under the counter. We like to cook but didn't use the kitchen for it since we chose this area to stay in Rome specifically for the food, and were eating bakery food or out pretty much all our meals. But, the kitchen probably isn't big enough for 2 people to be working in. You are in the foodie district of Rome, so you can hear music/restaurant/bar sounds until maybe 10/11 pretty clearly from the bedroom, but I think they turn off music and it slows down after that. Not loud in the mornings at all, unless you can hear the garbage trucks dumping the wine bottles. I didn't have a problem at all with the noises, my bf is a little bit more sensitive to sounds when sleeping though.
Bedroom: is the room with the air conditioning. It is the top floor apartment so the roof slopes down towards the end of your bed. I am pretty short but had to stoop to get around the bed, but no problem at all for the entryway or near the head of the bed to almost the end of the bed. The bed and pillows were a bit firm for us, which was okay for me after a day or two getting used to it but not great for my bf's back. It's a thinner mattress (maybe 8") that feels like compressed cotton, kind of like a futon bed. The pillows also have that compressed cotton kind of feel and were pretty flat, I used the airplane neck pillow instead while I was there.
Overall we enjoyed our stay in the foodie area of Rome, and would recommend Inca as a great host :)