We loved our stay in this apartment. It is beautifully appointed, very clean, spacious (we were four people), and the beds are really comfortable. Barbara was a very gracious and warm host, communicating well, and was very intent on providing us all of the assistance and information that might be helpful for us. Staying in this part of the city is ideal insofar as it is with a very reasonable walk to almost everything but isn't in the middle of the most tourist-trafficked areas.
The only small concern, as others have pointed out before, is the noise from the Campo outside at night. This is clearly a prime location for a lot of late-night gatherings of students and other young people, and it does stay bustling and noisy very late into the night. The windows are well insulated and the shutters help, and for four of the five nights we stayed there I didn't have any trouble sleeping, even in the front room facing the square. But on the fifth night -- a weekend, with warmer weather, it was loud enough that I needed my noise-cancelling headphones to fall asleep and the noise lasted late enough that I was awakened twice during the night.
In all other respects, it was a perfect place from which to enjoy a stay in Venice.