I liked this apartment the best out of 3 I stayed in on this trip. It is spacious and feels like home you can live in, not like an overnight-stay place. The location is central. There is a lot of stuff to see in walking distance, and three famous pizzerias to visit.
The only unexpected surprise was the "terzo piano" without the elevator. As far as I am concerned it was at least fifth, may be 5.5th. OTOH it is a good thing as it takes it well above the omnipresent Vespas. I guess it is a worthwhile compromise. Not every x centuries old building in the old city was (or can be) retrofitted with an elevator