The apartment itself is nearly perfect: very clean and modern looking, large and spacious, big and comfortable bed and the airconditioning worked flawlessly. Bathroom was also on the bigger side and the shower didn't feel cramped as some italians showers do, it was very comfortable! The kitchen wasn't too important to us personally but it had the basic requirements we would need. The host was quick to let us in upon arrival and also gave us some good recommendations restaurant-wise!
The location itself is great. You're not only close to the city center and to the biggest attractions, but you're right in the middle of one of the nightlife spots of the city. You're surrounded by pubs and bars and only a few steps away from the plaza where everyone gathers at night.
One thing you definitely need to keep in mind is that it can be quite noisy at night during the weekend when people go out. My partner is a very light sleeper and she had a bit of trouble sleeping on saturday since we had a Mount Etna tour planned the day after so we had to go to sleep early. Aside from that we had no issues sleeping. It's perfect for a young couple or friends who are planning to stay out till late. Just keep it in mind if you're an extremely light sleeper or if you prefer a calmer vacation with no nightlife or city noise.
Generally we didn't mind though and we had an amazing stay, so 5/5 stars!