Hi we just returned from two weeks on the big island. We did a couple of shore dives one at two step, one, just in front of our hotel/Condo (dont recommend the entry) but the turtles were fun to watch.
At two step we arrived early, watched the sunrise, then started the dive. Its a nice dive where the safety stop is just a nice swim over the coral as you head back. The problem we had on exit was the number of divers gearing up on the entrance. After floating in the water and realizing they werent going to give us room we opted for a different exit to the south. The surge was quite high that day and it made the exit a little rough for my wife. If you are experienced it should be no problem.
We were skunked on the Manta dive. The dive op said that only happens 15% of the time and offered us a "rain check" free dive on standby anytime we return. Very nice I thought.
I thought about doing more shore diving, but did find one advantage to the boat diving. On one dive, this is how it went. Humpback within 5' of the boat, but we left to go snorkel with the whale shark that showed up. A pod of dolphins then decided it would be fun to follow the boat do the dive site, so over the side we went. Sat on the bottom watching the dolphin show. Then continued with a great dive. Saw an eagle ray, octopus, and an eel strike. Kind of an overloaded dive. Worst thing was, we just got my daughters boyfriend certified and this was his first dive as a certified diver
We brought both 3mm and 5mm wet suits. The girls were freezing in their 3s and I much preferred my 5 with a hood. Especially when doing multiple dives. My wife only ever did two dives/day due to being cold. Bottom temps were 74 - 75 according to my computer.
Anyhow, have a great! time. Wish I was still there