We arrived earlier than expected and Marco'a mother Enza met us at the apartment. Enza spoke fluent English and told us all we needed to know about the apartment. We really appreciated that.
Location is not exactly central but it is only 4 minutes walk to the metro which can take you anywhere you want fast. It is also only 4 minutes walk to a small train station Roma Tuscolana which has a commuter train (TL1) direct to the FCO airport. At €8 (April 2017) ,45min, one train every 15 min, this is the best means of all to get to and from the airport.
Apartment is spacious and very clean. Kitchen is well equipped.
There is plenty of table and desk space. Marco is very prompt at communication and resolving any issues.
I highly recommend marco's apartment.