We did this excursion the last week in May, booked thru HAL, conducted by Allen Marine Tours (you may be able to get a better rate booking independently). It was great! The boat is a large, two deck catamaran that goes fast (35 mph) to get us where we needed to go but stopped rapidly and quietly so that we could observe humpback whales, bald eagles, harbor seals, and cliff-dwelling birds.
We saw two humpbacks, although the pilot said that they usually might only see one in a week. Rudyerd Inlet was unbelievably gorgeous - sort of Yosemite on water with bands of mist decorating sheer granite cliffs with waterfalls from melting snow on the mountaintops ranging from delicate trickles to splendid streams, reminiscent of the locales in 'Lord of the Rings.'
The on-board naturalist was not from the area but seemed knowledgeable, nevertheless (I always like getting a local perspective). The rest of the staff was friendly and helpful. Inside either deck (up or down) the visibility was good - but of course when there were great things to see we went outside (access only on the upper deck) so hats, gloves, and warmish coat were welcome.
My only regret was that the cruise went a little long - so we didn't have any time to shop in Ketchikan; had to dash back to the ship. But we were certainly grateful that the pilot took the extra time to let us observe the whales! And my pocketbook really didn't need any extra temptation.