The location is perfect. The room is nice and authentic but be careful the ceiling height is low for a tall person. And, if you are a person with limited mobility, this place will not suit for you. You can mostly done things around by walk or vaporetto with Guglie/S. Marcuola-Casino stop at 300-450m from the apartment.
At our arrival, we had a problem during the check-in and Valeria didn't hesitate offer to us Venice city tax and a refund of 50€ as compensation.
I highly recommand Valeria's place for a stay in Venice :)