Staying over at Marina's was like staying at a friends'. The place was smaller than I expected but still very nice and comfy. The bed is big, and although there was some noise from the street at night I slept splendidly. Even though she wasn't there when I arrived, Marina arranged for a friend to let me check in, even at a rather early hour. She only had one key when I was there, but again she was very helpful and flexible and it was no problem at all for me.
The flat is a bit far from the centre, but with the nearby tram 12 you can reach Duomo in 20min, so it's quite convenient in the end. Also very easy to reach Central station via bus.