We enjoyed our stay at Milly's place as the location / space was ideal for our purpose.
Damian (who is the acting host) was great especially in helping us getting our luggage (lots of them :) up and down the stairs and even helped us walk our luggage to our next airbnb a couple of blocks away.
The apartment is very clean and more or less same as the pictures. There is enough space for 4 people and maybe one other (smaller) person can sleep comfortably on the sofa in the study room. The location is great, in the middle of everything Palermo offers (bars/restaurants) but you don't hear the noise while inside the apartment.
Make sure you don't mind stairs because the building does not have a lift. The only thing that made is a bit uncomfortable is the contract we had to "approve" over email because it was unclear and some terms did not make sense /didn't translate well in English.