COMFORTABLE&CLEAN: I stayed with 6 friends in Federica's apartment for 4 days. The apartment is very big and beautiful (even more so than on the pictures), with enough space for sleeping for 7 people.
A shower in one of two bathrooms is not working, so we basically had only one shower for 7 people, which can be a bit tricky, but it wasn't such a big deal for us. The kitchen and the pantry were really well equipped, quite enough food for basic breakfast and everything for preparing a light meal.
Overall, the apartment was pretty clean, but a bit cold as the weather was changeable and the outside temperature varied. We asked for a heater, and Eriu was kind to provide us, somewhere in the middle of our stay.
LOCATION: It takes around 25 minutes to get to the center, but both tram and bus are literally a minute away, which was very convenient.
CITY: (note to future visitors:) If you plan to go out in the evening and come back after midnight, it might be a good idea to consider staying somewhere closer to the center, as it is virtually impossible to find a taxi in Milan during the night. The same situation is if you have flights in the middle of the night and you need to get to the station or to the airport. Eriu was kind to eventually help our friends book a ride to the station for 3 AM, when all our attempts to do it ourselves failed.
HOST: We never met Federica. Her friend Eriu was welcoming and helpful, but not always quick to respond, as we had to sometimes wait for several hours or even a day for her to answer.
In summary: a decent place to stay with a family or a group of friends, definitely better suited for longer periods of time (more than 3-4 days).