On our first day in SanFran we opted for the "Big Bus tour and Alcatraz combo".
Our main goal was to visit Alcatraz and the Golden gate bridge, and anything else was a extra ., If time ran out or we wanted to do something else we could easily jump off and later jump back on the bus.
Your offered Head phones when you arrive and can listen to commentary as you go around.
It takes a slow long route and for me had some boring parts , which had things we was not interested in.
Its a good tour, but for us a smaller vehicle could get to better locations and this is not easy to get off the bus and take Photo's . As your not allowed to stand as the bus is moving its difficult to take pictures of things on the other side of the bus .