We had a really good stay at "A casa di Ettore". Davide was a super welcoming host. It was really easy to contact him before our arrival and during the trip. When we arrived there was a wifi problem. He worked something out and stayed we us to make sure it was working. We had a ball on the table full of food, which helped us survive the next morning!
The apartment was a really charming place, clean and really close to center and everything to see in Catania. It is also not far from all buses going to Siracusa, Taormina, or the Etna, so it's really easy to move around!
The only thing we have to point at is that we had to pay a small tax at the end of the stay that we were not aware of : 1,50€ per person per night. It was not a big deal but we didn't know about it before the day before leaving.
We however had a great stay, and we recommend this place to anyone willing to stay in Catania! The streets around were really loud at night - good to know if someone doesn't like too much noise while sleeping!