Incredible location, spotlessly clean, great communications, no surprises. It's a big apartment for city center, with a Queen-sized sleeping bed and bath in upstairs loft, a real kitchen with washing machine, and another bath off the generous living room (which also had pull-out twin beds.) Location was easy walk to PIazza Novana, the Pantheon, and only 20 min walk to St. Peters.
We were there during a 100+ F heat wave of more than a week. The AC managed, but the upstairs loft was hot. (My kid chose it anyway). I took one of the pullout Ikea things under the stairs. It all worked out fine.
If you want to stay near the historic sites, this is a great place. Good restaurants (L'Orso 80) on block, and bodegas for the essentials. And the apartment itself is very quiet, the building well-cared for (nice doorman seemingly always around), there's a small lift for when you're dealing with your luggage.
Flavio and Emiliano were great hosts with great communication. Putting some more tips and instructions in the house guide would have saved them some texts from me, which they were always happy to answer but, I hate to be that kind of a pain.
PS: Would advise all visitors to Rome to use the bus system! We mostly walked until last few days and would have been a lot happier had we started busing earlier. With Google Maps set to transit, it's a cinch to take them. Buy your ticket at a tabacci. They run frequently, are clean, pretty easy to figure out, great sinage.