Good: the location cannot be better. You are close to trams, metros, and you can walk to all of the major sites (the Last Supper is 15 mins by foot and that is the furthest we needed to go). The apartment is a good size for two people and the air conditioning was a must as Milan had a heat wave and it would have been awful in an attic without it. It was very clean in the apartment. The washing machine was good but things take a long time to dry as it is an attic so keep that in mind. The host offered to fix the bathroom door right away and responded immediately to any questions. The instructions to get to the apartment and enter were very clear.
Bad: the bathroom door was not fixed when we got there even though a guest in June had mentioned it. The bedroom door was also broken. The apartment is very very basic: one sheet, two pillows, two towels per room, two rolls of toilet paper. No extras of anything. The kitchen is not equipped beyond two plates, two cups, two knives, one pot, one pan etc. There was no bottle opener, no corkscrew, no pasta strainer, no spatula, none of the utensils that you need if you actually want to cook anything. There was no dish soap or sponge or cloth to wash dishes, no dust pan and broom, no laundry soap. And there were no basics like salt, pepper, olive oil etc. Every apartment in Italy we have ever rented (over ten of them) has been stocked so that you can live there without having to buy dish soap, a dish cloth etc. This apartment had none of that. Eat out or do take out if you stay here. The second bedroom can only fit one person due to the sloping roof and it has no air conditioning: there’s a hole in the wall with a fan that connects to the main bedroom. It was very hot in that room.
Conclusion: stay here for the location and a clean bed.