Catania is an interesting city and is a great place from which you can also visit Taormina and Siracusa.
We got ok time but really nothing to rave about and nothing was simple. Food and cooking and buying at market is the best and so cheap and good
There is so much to explore in the little towns scattered around Mt Etna! Do not limit yourself to a visit up the volcano but also plan time to wander around the villages :)
Catania is a beautiful place to visit, there are so many things to see but everything can be seen in a day or two.
We went in December and 2days was more than enough to see everything whilst relaxing as well