Well, all what has been said before regarding this place is true. It's beautiful, close to everything you want and need to see.
We got picked up from the train station to make it easier for us to find our way to the apartment. Very nice!
Yes, the staircase smells like fried fish, but once you closed the apartment dorr you won't be bothered by it any more, no big deal.
The only thing that really bugged us was the water pressure in the shower. It's definitely not possible to take a shower/wash your hair, unless you're bald. The water just drips out of the shower and with thick curly hair like mine, you don't have a chance to get the shampoo out. So I just tried to wash off the sweat from a hot day and was done with it. Good thing we only stayed for two nights.
If you plan a longer stay this is definitely a no go.
Other than that, we had a great time in Venice :)