Marco was a great host! He communicated regularly with us with info on how to get to the apartment, and was there waiting at the front door when we arrived. After showing us around the apartment, he gave us tips about the areas of the city, and provided a detailed map!
The apartment is very nice, exactly like the pictures. Bedroom window opens to a private small courtyard so it's quiet at night. Extra pillows, blankets, towels, shampoo and soap available. Marco's apartment also includes nice little things like a Cappuccino machine and some biscotti. :)
Great location!
Tip (from Marco): Walk to the colosseum (SO close) and center of the city. Ride metro to the Vatican.