Regardless of the shop you choose I highly suggest Koloa Landing was a shore dive. I've been diving here well over 15 years and still dive there on my days off. While super rare ... we actually had a surprise visit from a Galapagos shark there in the afternoon yesterday! Few spots on the island can rival the critters that you will find there and your max depth is 45ft (averages around 25-30 generally). We had 2 octopus, juvenile and adult endemic green lion fish, turtles, several species of eels, horned helmet shells, frogfish, RARE squat anemone crabs, mantis shrimp, endemic freckled snake eels ... amazing. It's a protected bay with "relatively easy" entry and exit and has restroom facilities there. Parking is also much easier than on the north shore.
Most companies offer multiple day discounts of some sort as well. You can likely combine your shore and boat activities.
I'd suggest that any boat diving be done in the am as afternoon trips can be limited in dive site selection due to winds that come up in the early afternoon.
I think you'll find that all the operations here are very professional and have similiar styles and programs.
If you have any specific questions diving or otherwise please feel free to send me a personal message on the board and I would be happy to help you out anyway that I can.
Have a fantastic time planning your trip and a great weekend.
A
