We went whale watching with this company on our trip to Bar Harbor, ME. We went on the "Atlantic cat". This boat is huge and has three decks. The lower deck and a very nice refreshment area, the middle one had a closed deck as it tends to get very cold and windy when sailing in the Atlantic and the top deck is completely open and has the best view. The boat is extremely nice and I don't think you have to worry about getting sea sick as you can hardly feel much movement except for the cold wind blowing on your face. It is powered by jet engines, so they can go super fast. We did see a fin back whale blowing and then showing it's tail fin when it dived. The guide was knowledgeable about whales and the other creatures in the Atlantic ocean. But do go prepared with thick jackets and caps to protect your face and ears. It does get very cold when you are standing on the deck outside.
This company does give a money back guarantee in the sense that if you do not see a whale in your trip, they will allow you you come as many times it takes for you see a whale.... which I guess it nice if you live in that area. There trips are not cheap... $49 for each adult and $8 for kids under 5 and $18 for the other children.