To sum it : it's perfect. If you stay in Palermo, you should stay at Mauro's. His place is clean, looks good, feels great, and couldn't be more in the center of the city (it's literally in the center if you look at a map).

Plus, Mauro is awesome : way better than a guide, he spent time to explain us what we should see, and where we should eat to feel the real Palermo. Our stay there was awesome.