We had a great experience at Umberto and Martha's place. Umberto was very helpful-he met us at the nearby waterbus stop and helped us navigate to the apartment, with was only a few minutes walk. (A tip to keep in mind is that the #2 waterbus route only serves the nearest stop, San Samuele, between about 9:30 am and 8 pm, so check the schedule. You can use another slightly farther stop for the #1 waterbus in the early morning and late evening.) He was very thorough and enthusiastic at explaining how to navigate Venice and gave us a lot of great tips. The place was small but comfortable and clean and a good place to sleep after a busy day exploring the city. Recommended!