Well, it is hard to describe something from a critical point of view, if every remark appears to be on the positive side.
Cristina and Massimo were both very caring and kind. Interested in making a conversation and getting to know the other. Cristina helped us to make the best trips out of the short time with great tips, and Massimo brought his guitar to make a memorable evening. They made us daily breakfast (which was very delicious) and also an italian type dinner (also very good) one night. As someone pointed out, the whole thing reminded us very much to visiting a kind relative.
About the room, still not a single negative aspect: fine location (close access to metro), 24/7 guard service, seperate entrance, clean and cosy with our hosts changing the towels and cleaning up daily. Felt very private with only a few very basic rules, such as no smoking inside and being quiet after 10. We had our own key so we could arrive any time we wanted. Perfect to explore Milan for a fair price!