My wife & I stayed at Mario's place for 5 nights in late January/early February and it was everything we hoped for and more! The apartment is stylish, very clean, quiet, and perfectly located. The kitchen is well stocked and had everything we needed for breakfast and a couple of dinners in. Mario is an excellent and prompt communicator. He was quick to respond to any questions we had and he offered great recommendations for things to see and places to check out (and tourists traps we might want to avoid).
The apartment is a quick 35 minute drive from the Catania airport and it was easy to find parking- then we just left the car as everything is within a 5-15 minute walk: the island of Ortigia, the Greek ruins, supermarkets, etc.
As Mario notes in the description, the apartment is on the 3rd floor with no elevator (in the U.S. it would be considered the 4th or 5th floor), and the bedroom is lofted so you'll get some stairs in. We found it welcome exercise after all the amazing meals we had in the area.
We also recommend inquiring about Mario's experiences and taking advantage of his knowledge of the area. I booked a bike tour that unfortunately was rained out but he was completely flexible and instead took us on a tour of the surrounding area.
Grazie mille, Mario! We definitely hope to return and even stay a bit longer.