It's really a little cozy apartment with own door, key, toilet, shower. All is accurate and clean.
There is a good empty little fridge, we keeped our fruits there.
Location is fantastic. You can walk to the Termini railway station (buses to airport Fiumiccino are there), but if you prefer metro, the station Cavour is very close and the Termini is the next station.
Very many the most famous sights of Roma are near, you can walk there too.
The owner is very friendly and he answered our questions (via site airbnb) quickly. He gave us some good advices about the neighborhood.
The building is antique (I don't mean "ancient" ;) , just old and beautiful), it's like a sight in itself. Nevertheless, the interior is absolutely ok, shower room is modern.
So, we were extremely satisfied and even surprised: we just looked for something not too expensive in Monti but all was pefrect.