There's a ton included. If you plan only going to a few things then not worth it. But if you like to go to many different things for a short time, its a great value. And you get to skip the lines at the aquarium, which is a big deal during vacation season
ETA: let's say you are going for three days and know you want to do the aquarium, duck tours, museum of science and fenway tour. $33 + $23 + $22 + 16 = $94
Really easy to get another $6+ value
Exactly, we were there 3 days and did duck tours, museum of science, aquarium, children's museum, paul revere house, swan boats, fenway park, beantown trolley (more as a mode of transportation), sam adams brewery, and USS constitution. Would have priced out as well more than the go card was and it saved time. The other family we went with bought the 5 day ($40 more) and went to old sturbridge village and six flags/hurricane harbor after we left.