Alilaguna, public transportation boats or ACTV Public Transport in Venice, (vaporetto and bus)

I did not know about an Alilaguna pass, but seems too restrictive compared to an ACTV 72 hour pass, which takes you everywhere more frequently.
You can do the island tours on your own, but a knowledgeable guide can add to it.

This is a new thing to me. I've used the Aliliguna for transport from airport but can't imagine why you would need a 72 hour pass. A vaporetto pass would get you to the three islands and every place else in Venice. I also don't think 40 minutes would be nearly enough time on the islands. You don't need a tour to visit the islands as they are small very easily navigated by yourselves..
I highly recommend a vaporetto pass for your stay in Venice. It's really nice to hop on and off and not have to worry about the cost each time.

It is not a tour that I would do. 40 minutes total on the 3 islands is ridiculous. A stroll around Burano only would take that long. You won't have any time in Murano. The big thing in Torcello are the mosaics in the church. You won't have time for that, I wouldn't think.

The Alilaguna boats work reasonably well for transportation from the airport to the various parts of the city. The boats they use are quite low down in the water with enclosed cabins. The windows do get fogged up, and they get splashed so the view out can be obscured.

I know the city well, and when I rode the Alilaguna to my hotel last month it did a great job of delivering me right to the dock next to the Hotel Ala, but it was hard for me to see the bits of the city I knew I was passing and that was frustrating.

All in all, I would be careful with this tour.

On the other hand, a 3 day vaporetto pass will get you everywhere at your own speed. It is much easier to see out from any vaporetto, no matter which of the 4 types you are on. You can see the glass shops, and a furnace if you like, and the mosaics in the church on Murano, you can explore the brightly coloured houses at your own speed and maybe have a bite to eat on Burano, and see the mosaics on Torcello at your own speed, you just need a decent guidebook like Rick or the Green Book.

And you can put all that extra money back in your pocket.

It seems that the islands tour is a half-day, not 40 minutes. Still a very rushed itinerary, I would just use the vaporetto pass and spend as much time as I want on each island.

thanks everyone, that answered that question, and ACTV IT IS. vaporetto pass SOUNDS PERFECT.