I stayed in Matteo's room for 5 nights in September and I enjoyed my stay. The room is big with a comfortable double bed and nice en suite. There is no aircon so it was a bit hot but he provided a fan which was helpful. Matteo greeted me warmly when I arrived and showed me around the flat. I only saw him one other time as he usually works nights and sleeps in the day when I was out but I encountered no issues anyway. He also gave me space in the fridge to store food.
The apartment is outside of the city centre in a nice quiet area and it takes about 10-15 minutes to walk to the main attractions (duomo, etc). To/from the main station it's a bit further at 30 minutes of fast walking.
Overall, recommended for a comfortable stay in a relatively convenient location.