I will make it short. In my opinion, this is one of the best places to stay in Catania. Yes, it may be a bit loud but when you close the big windows and the shutters which are inside the apartement, you won't hear a lot of the traffic noise. It didn't bother me at all, I slept very well.
The apartement itself is more than fantastic! You feel like staying in a Palladian Villa.
No doubt, if I come back to Catania I will stay there again.