We used Jack's Diving Locker over Christmas vacation. Our three kids did their open water certification with them and we dove from the same boat. We also booked a shore dive, another boat dive, and the manta dive with them. We were pleased with all of our experiences.
Jack's seemed to make the effort to keep the kids diving with their instructor when we did the post certification dives. They were very helpful when booking and seemed to make the effort to accommodate our needs.
We dove from 3 of their boats- The Kea Nui, the midsized boat, and Diver Two. They were always thorough in their safety briefing before the boat left the harbor.
The staff was friendly in the shop and on the boats. I do not think I saw a frown once. Many of the staff appear to have worked there for many years. Which in the islands, can be a bit of an anomaly.
The diving gear that we rented was all in excellent shape. They seem to make an effort to keep people from peeing in the wetsuits, which means the wetsuits are not stinky!All of the boats we were on, had a large fresh water buckedt to use for underwater camera equipment.
Check in is at the shop, in downtown Kailua-Kona, pretty easy to get to. They then had vans that you could ride in to get to the harbor. You also had the option of driving yourself to the harbor.
They also had a great system for not wasting paper cups on board- clothes line and sharpie marker. Many of the dive masters had cameras and they offered CDs for sale( somewhat expensive).
If you had a dive computer, you were allowed to dive your air, if not you used the tables. They did have dive computers for rent, I believe.The dive groups seemed to be 5-6. All of the boats we used had fresh water showers to rinse off at the end of the diving.
We were impressed with the whole set up and plan to return in the spring for our kids to do their Adv Open Water!
As for where to stay, Kailua Kona area is probably best bet. Most of the dive boats leave from close to there. There are also plenty of places to eat in town. Jackie Rey's Ohana grill is one of our favorites!
kristy