Just got back from Kona a couple of days ago. I'd done the Manta Dive last year (with Neptune Charlies Ocean Safaris) and thought it was very unique but the swells made things a bit rough on the bottom. This time around, someone recommended the Black Water dive and Big Island Divers. They required you'd been on a night dive with them within 30 days to do Black Water so I did the Manta Ray dive again. We had 5 rays this time around but I realized that I don't really like sitting on the bottom of the ocean for 45 minutes holding a torch. I suppose it was better than being one of the three snorkelers who got sea sick on the surface.
Anyhow, the Black Water dive was fantastic. Turned my evening around. I got dropped in 5000 foot+ water, tethered to the boat with five other divers into this micro-alien soup. Biggest creatures out there were squid and the spinner dolphins feeding on them. The rest were a variety of pelagic weirdos in every direction you shined your light. It was a new perspective on the vastness of sea life in our beautiful oceans. In short, check out the Black Water diving!