First, the location is fantastic. A mere few steps from St. Mark's square and an easy walk to other main sites like the Rialto Bridge, waterfront, etc. The concierge kindly provided us with dinner recommendations, and although they were all booked (reminder to make reservations in advance!), his recommendation of Gio's at the St. Regis led us to come across the most charming terrace bar at the St. Regis with canal view which did not require reservations- I highly recommend for drinks, bites and pizza!
That said, we were very disappointed by our first room. I think your experience will highly depend on the room you get but Room 1155 was a tiny dingy room that smelled very strongly of cigarette smoke/old carpet and had the worst view (see photo attached). It was on a low level (Floor 1A) and faced a wall with a dirty tarp on the ground. The hotel should clearly designate the room as having no view and they should do a deep clean to remove the smell. The one good part about the room was the bathroom, which was nicely renovated.
The hotel was fully booked so we could not switch rooms that night, but we paid 40 euros to upgrade to a better room with canal view the following night, which was signficantly better. It was a lot more spacious with a table and 2 chairs at the foot of the bed and a canal view from the bedroom & bathroom.
FYI the entrance is the opposite side of what you see in the pictures but GPS took us to the right location.