Stayed at the Locanda Vivaldi & its good value for money.
Positives: Location is 100 metres from San Zacarria water bus station & 5 minutes away from St. Marks Square & 10 mins from Rialto bridge. Staff very helpful & speak very good English. They helped us book tickets to the "Venezia" musical, helped us with vital information on how to get where & were always at hand for any information required. The room was overlooking the grand canal and is good value for money. Breakfast was also good & the location is close to restaurants, bars & cafe's. There was a jacuzzi in our room which was a good relaxing experience after walking around (yes in venice you have to walk alot). They also tell you (accurately) the weather next day by leaving a card in your room along with chocolates. Free wifi in your room as well
Negatives: Only one - The internet speed was slow in our room, however it was fast in the lobby & this was the only reason i am leaving out one star in the review.
Would give it a 4 1/2 star.