I think for a first time visit to Hawaii, or for your 20th time when you have seen it all several times, a cruise is the way to go. But even then, I would prefer the NCL type where you don't have 8 days at sea. And those type do have an overnight sometimes on Maui to accommodate the sunrise. At least we did, when we cruised many years ago. But after our cruise, we went back to Kauai for three days and then back to Oahu for three more before flying home. This Oct, we are going to Kauai for our 40th anniversary for about 10 days.
Since then, we have been back to Maui for a month and a week for a wedding, plus a few days in Oahu. But the cruise gave us an opportunity to see some of the highlights and decide what we wanted to go back and see. But the comments about port times is true. I would take the cruise with the most time in ports over any other consideration. The cruise us cheaper than the land part due to the food, even though, we don't do fancy resturants, look for bargains. Just the idea of having to buy macadamia nuts or pineapples after having all we wanted on ship, was a big shock!!!