If you want to stay in a non touristy, not so busy area where real Venetians still live - this is the place to be in Venice. We really liked Castello and the really quiet area around the apartment and nearby Via Garibaldi with nice cafés and busy local life. We walked everywhere from there but the Vaporetto stops Arsenale or Giardino are also nearby.
The apartment is very nice and looks exactly like on the photos. What was described as four bedrooms I would really only call two bedrooms. Each has a big upstairs gallery with double beds. So there are beds for eight people. But due to its shape and size, I would not recommend it for eight adults. But each of these two bedrooms have their own private bath, so you have two really separate areas. This from my point of view makes it nice for two couples maybe with children or one bigger family with several children.