My husband and I dove with Dive Makai about 4 years ago, and we also were staying at the Waikoloa. At the time, neither one of us were certified, which may make my reply very relevant to your trip. I had been on 5 resort dives over a period of about 10 years, and my husband had been on one very horrible resort dive in Maui that soured him to the whole scuba experience (the instructor was a jerk, didn't teach my husband how to use his BCD, overweighted him with 25 lbs. which sent him to the bottom immediately (my husband sinks naturally and only needs about 5 lbs. to be neutral), and after that sent my husband back up to the boat alone!). So for me to talk my husband into trying scuba diving again was a huge feat--and the folks at Dive Makai did a FANTASTIC job making him feel comfortable after such a terrible prior experience. We went out with three certified divers at two different dive sites. We were on the "intro dive", which only included one dive, so while the certified divers were in the water at the first stop, the DM put a tank in the water with a reg and a BCD just to float on the surface so that my husband could just hang out and get used to the feeling of breathing from a tank, just like as if he were snorkeling. He was so comfortable with the DM, and felt so relieved after this exercise that he absolutely loved our dive. The DM was great--pointed out a lot of neat critters, including a crown of thorns starfish, which my husband was really excited about. We had a great time with Dive Makai and will probably go back to them this May, when I'll be getting my AOW. My husband already has his AOW (got it in Florida last year while I was pregnant)--and I am very confident in saying that without the great experience he had with Dive Makai, he would never be a certified diver, let alone have the advanced certification. That said, now that they changed hands, I don't know how much of this is applicable, but hopefully they'll still be a great op.
One more tip: when we stayed at the Waikoloa, we had a room above the dolphin pool. At night we opened our balcony doors and listened to the dolphins splash and squeak right below us. It was very cool.
If this sounds neat to you, maybe you could try and request one of those rooms.