I took this cruise with my friend, she took the anti nausea pill and it made her so sleepy she missed most of the cruise, so unless you really need - pass on the pill.
You'll definitely get to see dolphins and seals, but when it comes to whales it depends on the season so do your research before if it's the right time.
We got to see whales from a far and not too close, it also feels like you are in a stakeout to catch the whales as they come out to breath.
The woman on the boat tells the crows to pick a side of the boat and that when a whale is spotted the boat will turn. What actually happens is that people run to the side where you see the whale and then the boat turns (useless) and everybody runs to the other side to continue watching it - so why turn the boat ?!
Overall it was fun, and I would recommend it.