My parter and I stayed at Chiara's apartment for 3 nights and really enjoyed our stay. The apartment was in great location with San Babila train station at our doorstep, close to a small supermarket, just a short walk to Duomo square and cathedral and surrounded by fantastic shops, cafe's, bars and restaurants.
The apartment was extremely clean, modern and nicely decorated and also had a very comfortable bed. There was good air conditioning and good and fast Wifi. As non smokers we were also really happy that the apartment had no smell/evidence of smoking from previous smoking tenants.
Chiara arranged for her mother to meet us on arrival and she was really friendly showing us the apartment and explaining some of the sights to see near by. Later on after Chiara finished work she too came to introduce herself and was really lovely and friendly offering to assist if there was anything we needed.
The only very very minor negative that I can think of would be that you can hear a very mild rumble from the metro station and occasionally what I think were church bells chiming, however this wasn't an issue for us and would not deter us from staying here again.
Overall we had a fantastic stay and would highly recommend staying at Chiara's apartment in Milan.