We enjoyed our stay at Guglielmo's flat very much. We did not meet him personally as he was out of town. But his very friendly assistant met us in the flat to welcome us. She had great tips for us and took her time to take us through the flat and to answer all our questions.
The flat looks stunning and was very clean as on the pictures and the location is brilliant. Just a few minutes walk from the vatican and near the underground. Guglielmo had a tablet and modem for us to take along, which was very helpful. Generally, we found that around the main tourist attraction food is not that great and more expensive. But there are good ones in his street. Actually the best one we found on our journey in Rome is just around the corner (2 min walk) and they also serve gluten free pasta: Trattoria Da Romolo, outstanding Italian food.