We got certified with Lahaina Divers and found that although they run a bigger op, the DM's are really wonderful and they provided very good service. Of the 4 charters we did with them, on only 1 were there snorkelers, and the staff definitely focused on the divers not the snorkelers. We also found that although the DM's do the turn around at 1500 psi of the biggest Hoover in your group, they also let those who weren't at 500 psi under the boat to stay down and snoop around for awhile longer.
One advantage for the newbie is because the boats are so large, they are incredibly stable in the water and have excellent dive decks. Getting in and out of these boats was a piece of cake, and the smoothness of the ride helped me not worry about getting sea sick. I definitely appreciated all of these things when I was getting certified and right afterward.
We dove on a 12 passenger in Key Largo recently and I agree that I prefer the smaller boats overall. We have a private dive charter scheduled for Tortola in December, so it's going to be fun to compare the bigger boat experience to the private dive charter experience. <G> Might be hard to go back to anything bigger than a 6-pack after diving from a "2-pack". <ha ha ha>
Lahaina Diver's location is excellent for those of us who stay on Kaanapali, so that's a driving factor for us to not select a dive op in Kehei. We go to Maui every year (timeshare), so establishing a relationship with a dive shop is important, and we are always treated right by Lahaina Divers. If that ever changes, I'm sure we'll be seeking another shop.
