So here is the short version: great place to stay for a few days and see the sights if Palermo. I would go back again.
The long version: this place is not the best and it is not the worst place I've stayed in. When we got there we were greeted and shown around the apartment. We were shown how to use everything and where everything was.
During the night on our first day, the power went out and alarms in the building went off at ~3:00am. I'm not sure what happened but this lasted for the entire night. It would go on for 5 - 10 minutes then off for a little while. I don't know if it was us or another unit in the building that was causing these issues.
Secondly, the wifi was knocked out the day before we arrived and was not fixed until the following week. The cable guy arrived before Valentina and we had to work with him to find out where the problem was.
A few people have commented on the smell that comes from the staircase to the balcony. Yes, there is a sulphur smell. No, it is not overpowering and it does not leak into the whole of the upstairs or the balcony area. I understand that because we are on the top floor, there is no place else to put the vents for the drains so you have to live with the smell. It only stinks when you have to climb to the balcony. It is manageable.
I found the water pressure to be adequate but found drainage to be an issue, a lot of times we had to wait 30 minutes for the water to drain so the next person could go shower.
Now, aside from all this, I would stay here again. My reasons behind this are simple. I do not go on vacations expecting that everything will be perfect and that it will be like staying in my home. I know that these places are shared amongst many other travelers who all use the same areas we do, and it can be hard for the owner/manager to keep track of all that is going on with the place unless someone brings up an issue. Knowing this, I would go back in the hopes that things would improve.