This was a fun experience!
I thought it was a little spendy at $20 per person for a 10 minute ride, but they do make it fun. A little bummed that the outside ride was not operating when we were there, but our boat operator was awesome - he sang to us, he gave us lots of trivia about Venice, asked where we were from.
The scenery was beautiful and it was fun going under the bridges. Parts of the trip were "daytime" and parts in the "dusk" - it was overall a nice treat and we would do it again.