Venice has plenty to offer with walking and taking a gondola, so we didn't need an excursion.
We organised our own private tour guide as there was 10 of us. The gondola ride up to the top was spectacular.
Not the best port of call. We missed the bus tour of the town, not enough buses. The taxi drivers fought over us. We had 2 taxis and they piled 6 in one taxi and the 4 of us in the other, which was quite ridiculous.