My only experience has been with JDL. My recent trip was May 2024, and here's my trip report.
A Little Background. This is the fifth and final segment of a 50-day trip that started in Fiji, continued with an 18-night cruise from Sydney to Honolulu, then diving on The Big Island, Hawaii.
Starting in Fiji, here’s the order of my travels and the trip reports.
Paradise Taveuni, Taveuni
Trip Report - Paradise Taveuni-March/April 2024
Volivoli Beach Resort, Rakiraki, Viti Levu
Trip Report - Volivoli Resort, Fiji-April 2-11, 2024
Sydney, Australia
Trip Report - Sydney, Australia-April 2024
French Polynesia, Papeete & Raiatea
Trip Report - French Polynesia...
The blackwater dive is well worth it at JDL, and I like that you are tethered to the boat, unlike in other places like Florida where you're free floating in the dark and you have to keep a constant reference to the down lights, which, IMO, takes away from the experience. I don't know how the other ops do it on Kona, but I believe JDL was the first dive op to come up with this adventure dive.
I would not recommend JDL for reef diving. They've turned into a student mill and the sites are over-dived and boring.
I've had very enjoyable manta dive experiences with JDL. If you get Keller as your guide, he's the manta expert and can identify all the mantas by name and markings. His enthusiasm for the mantas is genuine. The dive site is a big commercial operation now with many boats of divers and snorkelers. Their setup is a bit different, though, than other dive ops. The first dive is a late afternoon/twilight dive, and they get to the site very early to get the best mooring. Then there's a very long surface interval, like 60-90 minutes, because they get you in the water halfway through all the other boats' dives. So, a few minutes after you're in the water, everyone is leaving and you get the site to yourself. It's soooo worth the wait, especially if you're a photographer. Keller always has a camera and he shares his photos and videos for free if you have an Apple phone. You're out of luck if you have an Android. He's taking the pictures for ID purposes. Years ago, he would sell his photos by putting them on a DVD at the shop post-dive. Back then, before everyone had a camera, his shots were taken with an eye toward selling the memories.
Here's are some videos I put on my YouTube channel.
Blackwater Diving-Kona, Hawaii-May 2024
Blackwater Diving-Kona, Hawaii-May 2024
Blackwater Diving-Kona, Hawaii-May 2024