Firstly, you should know that you will get colder than you can imagine on this trip. No matter how many layers you wear, you will need more. Make sure you use one of their all in one boiler suits or else you will freeze.
The stop near the puffins is pointless. They are so small that you can hardly make them out, even using the zoom on the camera lens. I appreciate that if you want to see puffins, you should go on the puffin tour, but then leave this bit out and speed things up a bit.
We saw a few whales, but always at a far distance and very briefly. At this point, we felt so cold that any enthusiasm for whales had ebbed. The minke whales keep far away from the boat. Since they are still hunted in Iceland, this seems very sensible self-preservation on their part.
Also, although our trip started at 5pm and was advertised as 3 hours, we did not dock back until 9pm. By then we were cold, bored, tired and regretting the decision to do the trip at all.