The trip did not start out well (with misplaced passports my fault coupled with a lot of fault by Delta airlines who found the passports and locked them away until the next day causing us to miss our plane) and lost luggage both Delta and Alitalia's fault). We spent much of our day in Florence chasing our lost luggage. We didn't have our luggage for the first few days. (we had to shop in Nice). We missed Barcelona (because of the lost passport problem and had to take 5 planes to get to Nice (second port).
Venice was our favorite port (we spent 2 days there). (But watch the high pressure Murano sales people.) We stayed at the Hotel Grand Canal which was very nice for the last day. Venice was the final stop.
The porters at the airport (after arriving by water taxi extorted 40 euros to bring our bags to the airline gate (We should have traveled by land not water taxi (which also charged extra for our luggage)