I stayed by myself in Giovanni's room for a single evening and I highly recommend it.
My experience with Giovanni was absolutely positive. Giovanni in particular was really kind and generous. Even though the check in was only at 3pm, he allowed us the leave some bags at the apartment in advance (at 10am). He provided a very clean room with really nice amenities. The bathroom was huge and really clean. The internet was exceptional. And the balcony was absolutely spectacular. I had the feeling that Giovanni was really doing all he could to make my stay as pleasant as possible.
Minor issues that may be a concern for some is that the AC is a bit old, and he recommend us not to let it on the whole day. Which for me was fine, because I spent most of the time at the balcony and I really enjoyed the fresh air that came from the door/window. The curtains may also be a problem for some, since it doesn't block the sunlight so much and I could not completely understand by myself how it worked.
Overall, I had a great experience and I would highly recommend his place to anyone visiting Catania. I hope I have the chance to stay there again and enjoy a bit more of the balcony.