I had a really great stay at Giusy's apartment. I was there for over two weeks and as a solo female traveller, I felt very safe as there are three locked doors between the apartment and street level. The apartment is very well-equipped, with an excellent mattress, pillows and powerful shower. There is also a full kitchen, comfortable sofa, good air conditioning, patio and balcony. Giusy was very easy to reach via Airbnb and messenger and answered my questions quickly.
I work online and the Wi-Fi worked well, although I suggest bringing an Ethernet cable with you so you can connect directly to the modem. I did this as the internet briefly cut out twice over my 16 night stay. You should also bring ear plugs as the bedroom is next to a neighbour's living room and I could hear them some evenings (watching TV until 11pm or midnight).
Location-wise, it is very convenient; 10 minutes from the train/bus station, 10-15 minutes from Ortigia island, 5 minutes' from a Conad supermarket, close to restaurants, gelaterias and cafes. Prices are lower in Siracusa than on Ortigia island, and it's less touristy so it's a great opportunity to live like a local and practise your Italian. If I visit Siracusa again, I will stay at Giusy's apartment!