We had a very nice time at Martina's apartment.
It is located in a beautiful area, with cafes, shops, supermarkets, etc really close. As other comments mentioned you can hear the buzz from the street but it was not an impediment for me or my kids to sleep. It was really easy to communicate with Martina, and she was really nice and helpful (lots of cultural recommendations). Martina also tried to make our stay with the kids as comfortable as possible which I really appreciate.
The flat is comfortable and well equiped. Heating and hot water worked with no issues which was great as our visit was in November.
I highly recommend Martina's flat for a lovely visit to Venezia.