You can go to a website like
http://www.affordabletours.com/ and see what else is available. You need to learn how to read an itinerary. "You will see" means the driver will slow down and your guide will describe it as you drive by. "You will visit" may mean you're on your own. Words like you'll tour means you'll actually be taking a tour.
Last time I checked Perillo includes more meals then most of the other tours Perillo also includes wine with your dinner.
Trafaglar and Insight are two other tour operators to check.
The cheaper tours don't offer much more the transportation and lodging. The more expensive ones also include some tours. The more expensive tours include lodging close (within walking distance) of the sites. The cheaper tours including housing in the outskirts of the city.
This is the budget board. You can check tours like Gate1 and Cosmos. The base price is lower but you'll be paying for more as you go.
When I toured with Perillo the morning tours were included. Afternoons we weren't traveling the tours were optional (extra cost). Most people took most of them. I think some of the tours that were optional for us are now included.
The better and more expensive tours, will have you staying on the main island of Venice. The cheaper tours make Venice a day trip, have you stay on the mainland or one of the other islands.