Although we dive Lanai with Lahaina Divers when we're on Maui, and really enjoy our charters with them, they do take a lot of divers on their boats and some consider them a "cattleboat" because of it.
My definition of a cattleboat doesn't so much have to do with the number of divers, instead it has to do with the mentality of the op, the services offered, the ratio of bodies to space on the boat, and the type of diving. For instance, I've been on a boat with 9 other divers that should have held no more than 6 divers. The operator limited our bottom time to the person who sucked their tank the fastest (turned out to be 35 minutes with a max depth of 50'). They didn't offer water or snacks on the boat. The dive guide simply swam us over the reef, never stopping to find any critters and got impatient if anyone else did. The rental equipment looked as if it had been run over by a car several times (we weren't renting), etc., etc., etc.
On the other hand, although Lahaina Divers puts up to 22 divers on their boats, they run big 46' Newtons with oodles of room for everyone. We found that if we avoid their afternoon charters (the Discover Scuba ones) that we've never had more than 18 divers on the boat, and have had as few as 12 a couple of times. They also provide water and lemonade, snacks during the SI and warm cookies after the 2nd tank. Because we dive with computers, we're always given the latitude to stay in the water longer, and can even go off on our own if we choose (after speaking to the DM's of course). They divide their groups into 6-8 max (usually 6), and the DM's do a good job of finding reef critters.
IMO Lahaina Divers is a quality operation that provides a good product. They are geared more toward the occasional or beginner diver and do an excellent job with those folks. Since we know all this, we enjoy our dives with them to Lanai (and will continue to use them for Lanai), but choose Ed Robinsons for our Molokini charters as they are geared toward a more independent diver.