Go Boston card was a great money saver. We enjoyed many museums, tours and trolleys with a very positive experience. The only negatives the employee at Macy's gave us wrong information about were to take the tours and the card was not valid at Fenway that day,sowehadtocomebackatalaterdate.
This is a silent tour. No comment from any tour guide or the driver. It was just a quiet ride around the pond with the occasional quacks from the ducks.
We used the three day card. It was great. As others have written you cannot get to everything. We did quite a lot in three days and the card made it so easy. A few sites aren't connected with the card so make sure to check the guide book. That was fine with us. A third day on the trolley would be a nice addition. Also we chose the whale watch and couldn't have been happier. Overall my husband and I give the card two thumbs up!