I did Oahu and Maui and enjoyed both. Lots of wrecks with easy access at Oahu and Molokini crater off Maui is the bomb. They each have their unique options for diving. Don’t forget to weigh the between diving options as well. Maui has the road to Hana that’s the most scenic twisting turning drive you’ll ever have. Over 600 hairpin curves with nearly 60 narrow bridges of which 46 are one lane.