This is a highly recommended place to rent, very good choice on all accounts.
It's perfectly located, in an atmospheric neighborhood close to the old Jewish district, at a quiet end of a street running along a canal. At the same time it is within a 10 minute walk of Fondamente Nuove (where you arrive from/depart to the airport by boat) and within 20 minute walk of San Marco.
The apartment is big, comfortable and clean. Spacious living room connected to a big kitchen with a big family table and several windows overlooking the canal. Two bedrooms with good double beds + sleeping space for at least 4 in a mezzanine, very big and well equipped bathroom.
Massimo makes a great host - helpful, knowledgeable about the city, with perfect command of English. He can take you for a ride with his boat, but we decided to ask for a walking tour to take better advantage of his knowledge of the city. It would have worked perfectly - but for dozens of phone calls that he received over the hour he spent with us. But his knowledge and communication skills are impressive nevertheless.