First and foremost, the location in Palermo can't be beaten. It's close to everything, not too sunny, not too shady, and steps away from pretty much anything. The apartment itself was very clean, and had all the amenities one would want. The WiFi was mostly very reliable, and so was the AC and hot water.
However, there were 2 major noise issues during my stay, which made working from the apartment mostly impossible. First of all, from the first week to the last, there were major construction noise literally under the apartment. Jackhammer and drilling type of noise, from 8am to 3pm, 6 days a week. Unbearable.
Second, the building entrance has an alarm that rings whenever the front door doesn't get closed quickly enough. Residents of the building seemed to not pay very much attention to the door, such that I had to go close the door myself every other day (the pitch is so high it can't just be ignored).
If it wasn't of the noise, it'd be a 5*, but I'm rating according to my stay.