We did not meet Duccio in person, but he left a very detailed welcoming letter and nice instructions how to find the flat and get the keys, so the check in was really easy. He was also very responsive when we had questions or concerns.

This indeed is a very nice apartment 300 m from Duomo, close to everything in the center of town and surrounded by little cafes, shops and with a convenient grocery store on the same street. We also appreciated that there were books about Italy, especially the guide for Uffizi and the history of Renaissance. However, there are a couple of things one needs to keep in mind when considering this place. It is listed as the 4th flour, which is how it is counted in Europe, but in US it would be considered 5th. And, since it is a proper European building, the ceilings are high, so it is a lot of stairs. This could be a problem for older travelers. Also, the washing machine is out of order, though Duccio mentioned that he plans to replace it. We also had some issues with the gas stove, though the temporary solution was found. Also the master bedroom, though it is very beautiful, gets a lot of noise from the street, so light sleepers would sleep better in the smaller one.
All in all our experience was positive and I would recommend Duccio's place for a pleasant stay in Florence.