Unlike other locations popular for snorkeling, this one goes to two reliable locations that aren't going to be unavailable due to weather. Honolua Bay, which is extremely calm, zero current, and a great reef. We saw many turtles, lots of fish and over it was great. The second location was the Cliff House (though they may do others for the second, depending on conditions). It was a great spot as well.
The boat holds 49 people, and the trip I took had that many. It did not feel overcrowded at all. The boat is laid out and sized appropriately for this large of a group, and is a pretty comfortable ride. Lots of seats with cushions, lots of places to get out of the sun and a fairly spacious bathroom. Lunch was great (exactly as advertised), and the sail back was incredibly relaxing. The staff were professional, friendly, and helpful.