If you want somewhere central to the sites then this is the place. We couldn't believe we were a few minutes away from Piazza Navona and the Pantheon. We could have stayed for a month and not eaten at the same restaurants twice - there is an amazing array of restaurants within a few blocks radius . Marco was extremely responsive to all of our questions and even helped to arrange transportation the morning we flew out. He is a very gracious host who is more than happy to help. His apartment does have the major advantage of having a dryer along with a washing machine (something we didn't get throughout the rest of our European trip) so that helped tremendously. The air conditioning was a much needed amenity due to the 100+ degree heat while we were in Rome and the rooms stayed very comfortable throughout our stay. As others have mentioned, the stairs to the first bedroom are a little quirky but they are manageable if you take it slowly.
We would definitely stay here again because of the host, amenities, and proximity to the heart of the city.