We stayed at Cristina's apartment for three nights in mid August. It was a fantastic experience. Some key facts and info:
1) We were over an hour late to meet Cristina and didn't arrive Rialto Mercado pier as instructed. Instead we arrived Rialto pier which is on the other side of the canal. Although it was not far from the apartment, it can be an ordeal to walk through the crowd at the Rialto bridge with luggage. Cristina was very accommodating and helped my son with his luggage to get to the apartment. She greeted everyone of us including kids when we met, gave us a warm welcome even after the delay.
2) The apartment is only a few minutes walk to a wonderful wet market (Rialto Mercado) where we bought fresh seafood, fruit and veg at reasonable prices. It has added much more flavour and local experience to our time in Venice!
3) A casual bar/restaurant, seafood takeout, another restaurant and coop supermarkets are literally just downstairs, can't be more convenient.
4) If you want to take line 2 vaporetto and want to avoid the crowds at the Rialto bridge, another pier 'S Toma' is only less than 10mins pleasant walk.
5) Finally, needless to say, the apartment was comfy, clean, Cristina was very responsive, friendly, gave us a map with recommended restaurants and home address already marked, very organised. I felt like I made a new friend!

All in all, the apartment and warm welcome from Cristina definitely added to our enjoyable time at Venice. Highly recommended!