So, it seems like the best choices are either Capt. Bill's out of Glouchester or New England Aquarium Aquarium Whale Watch (Boston Harbor Cruises). Both "guarantee" seeing whales and both have a naturalist on board. Costs are comparable. It seems to me that the key is to know which actually offers the best experience. Here are the factors that would be important to me:
1. time actually spent with the whales (versus time spent getting out to the feeding grounds)
2. stability of the vessel so as to decrease the potential for sea sickness
I understand there are also good trips out of Provincetown, but we will be staying in Waltham and taking a morning trip and it seems like the drive to Provincetown is unnecessary to meet our goals. Am I correct in assuming this?