Al Mialkovsky:
Yea they spend some time talking about critters before every dive. I don't think they call it a dive "briefing". They have to use another term. For many people that's what they want, others just want to get wet.
If you want to learn about turtles, ask Andy about his turtle survey and he'll get out his book with hundreds of photos of turtle head and neck patterns with info on when and where they were spotted.
Willy Gilligan, there are lots of good operators. Out of Kihei; Mike Severns, Ed Robinson's, and B&B run 12 passenger boats that consistently get good reviews. That's my sequence of preference, but that's because I'm a fish nerd.
The 3 dive ops each have their own personality, but I'll gladly dive with any of these 3 high class operations.
Scuba Shack, another 12 passenger boat out of Kihei, reflects the varying personality of it's owner, Charlie. I'll call him to book a spot before I call Maui Dive Shop or Lahaina Divers, but only after I've called all of the other Kihei 12 packs and 6 packs. I don't have any real reason. Just personal preference.
For trips to Lanai from Lahaina, my strong preference is Extended Horizons. The Hawaiian Rafting boat is a lot wetter and rougher ride.
Lahaina Divers and Maui Dive shop are the two large dive ops on the island. I've had good trips with both, but unlike the smaller operations where the owner is involved in daily ops, with the 2 big guys the experience will vary more according to that particular crew. I do recommend Lahaina Divers for trips to the Lanai Cathedrals for divers that are prone to seasickness, as their bigger boats are more stable on the sometime windy and choppy return trip.
Makena Coast Dive Charters, Dive and Sea Maui, and ProDiver Maui are six packs out of Kihei. even though I had a great trip with them, Dive & Sea Maui isn't on my shortlist because their boat doesn't have a head. Prodiver Maui has a nice boat, but relatively inexperienced Captains and DMs.
The Maui Diamond II runs a mixed snorkel/scuba/discover scuba boat to Molokini from Maalea. I generally prefer pure scuba trips, but if you want to do a trip with a non-diver, this is a possibility. The Maui Diamond II owner/captain Jeff is, however, the guy that left 8 divers in the water for over 5 hours back in Feb 2003.
Some snorkel boats, such as Trilogy, say they do scuba diving. I don't recommend them for certified divers, as they are really snorkel boats that also do Discover Scuba. I've enjoyed trips on Trilogy's boats, but rather than doing a dive at a site chosen for depth and closeness to a snorkel site, I just went ahead and snorkeled with my guests.
