Wow! What an amazing place is Siracusa, and Mario's apartment puts you in the beating heart of the city.
Siracusa's jewel in the crown, the island of Ortigia, is a very short walk away. It offers many culinary delights and lots of things to see.
But my wife and I equally enjoyed staying in an apartment block on the other side of the bridge surrounded by Sicilian neighbours, and giving ourselves a break from other tourists during our three-week stay. Some days we didn't even cross the bridge, ate pastries and drank espressos for breakfast (entranced by strange traffic rituals and people going about their days), popped into a patisserie for tempting morning tea (just don't tell your doctor about the cassatta, panna cotta etc), found restaurants or pizza places for lunch and went to a bar for a cooling Spritzer at the end of the day.
Mario's apartment was well appointed for our longish stay.
Mario not only advised us of some of the best places to go, he organised transport for day trips we requested. We had two memorable excursions: one to Ragusa, Modica and Noto, and one to the amazing Roman villa at Piazza Amerina. I'd give him top marks for making sure we were happy.
Now the downside. Noisy, frenetic traffic goes with the territory of being in the beating heart of the city. The traffic noise finishes late and starts early.
The apartment is up four flights of stairs, which older folk probably won't want to do too many times a day. My wife and I are both on the wrong side of 60 but it wasn't a great problem for us. We were very grateful Mario carried our suitcases up though.
We landed at the apartment in the middle of major renovation work, which meant the building was swathed in scaffolding for the entirety of our stay. Heavy rain probably delayed work a bit, but we were literally high and dry.
Work on the facade started early but finished at a reasonable hour. We had no such luck with major work going on in the downstairs apartment. Sometimes we had duelling jackhammers till midnight.

All I can say about this is our misfortune will be someone else's good fortune. As they say in Italy, the place will be perfecto when the work is done.
We'd certainly want to stay in Mario's apartment again — though that traffic noise is unlikely to go away so we'll be sure to bring extra earplugs.