Do not do this tour if you visit in the summer as the fog was cold and windy and the fog will ruin your views of the Golden Gate Bridge (we couldn't see it at all) and Alcatraz. Food bad too. I booked an afternoon one for half the price with same cruise company through viator and it was INCREDIBLE
Very enjoyable cruise, free drink and appetizers included, plus musical entertainment and commentary about points of interst on route.
Plus you get to go under the Godlen Gate Bridge which is surely the highlight.