Cinzia's place is within a 5minute walk from St. Mark's Square in an excellent looking building; we saw many people stop to admire the outside facade! There is a gondola just outside if you are so inclined, and there are supermarkets within 2mins walk (and plenty of restaurants).
The place itself is quiet, the main room is spacious and has the facilities you need for a few days (the oven wasn't working when we were there but didn't cause us an issue). WiFi was slightly temperamental but Cinzia was able to reset it for us which improved things considerably. We stayed for a week and it was a great place for us!
Cinzia was excellent at communicating with us and also provided several tips for restaurants and travel around Venice.