I dove with Steve in Maui on most of the shore dives but did not do any boat dives. Personally, since my family does not dive, shore diving was a great option vs. the boat dives since the family hung out on the beach and I was able to snorkel or boogie board with them after my dives.
Regarding diving vs. snorkeling, I think they both have advantages and disadvantages. In general I prefer diving vs. snorkeling since it allows you to get closer to the fish to take better pictures and see the smaller fish and eels that you might miss snorkeling, especially the little puffer fish that are only about 3 inches long. I also think its a little easier to take pictures under the water vs. bobbing on the surface. When I dive, I prefer to dive mid reef vs along the deep edge since there seem to be more fish in that zone.
One advantage that I feel snorkeling provides is the ability to dive in very shallow 3-4 feet water along the top of the reef. I like to do that just to see the different and smaller fish in that zone and additionally there is better light for my ancient underwater camera
. A couple of thoughts on the places we dove:
Kapalua has shallow water and reef on the left and deeper reef on the right sides. I think the snorkeling is as good as the diving here, however, I did see some stonefish and other fish on the reef that would have been impossible to see snorkeling.
Makena Landing (5 caves) has an intermediate shelf that is good for snorkeling, but if you want to check out the white tips snoozing in the caves, you need to dive to check them out.
Black Rock seemed to have more of a wall reef. We met a snorkler coming out when we were going in who claimed not to have seen any fish, but we saw plenty diving including a six foot white tip in the open sand between two reefs.
Ulua reef has great snorkeling around the shore reef, however there is another deeper reef that you need diving gear to reach and explore. I thought the second reef was a cooler reef, however the reef close to shore has more fish. Another advantage of diving here was that the visibility close to the shore was bad, but the vis at the second reef was much clearer.
I snorkeled Olawalu (Mile marker 14 last time) and there is a great reef for snorkeling, however there are turtle cleaning stations in deeper water that you would need to dive to see. I was not able to dive Mile Marker 14 this time.
Either way, the diving is incredible, so have a blast. I recommend contacting Maui Dive shops and getting their Dive book. It was quite helpful to plan both snorkeling and diving.