I did a 7 day Hawaii cruise on NCL with the all US staff. DH was worried about being bored in hawaii (he's not a sit on the beach and relax kind of guy), and I don't think I ever would have been able to decide which island to visit. I loved that I got to sample every island. Maui and Kauai were overnights, so we had a good amount of time to check them out, Kona was a really hard stop since it was a tender, and the car rental place is so far from the dock. We only had a few hours, but it was probably *my* favorite few hours of the trip. We did rental cars in every port, we were there with DH's parents, so rental car for 4 was much cheaper than the excursions. We did a lot of the sites that the excursions did, but managed to hit most of them before the bus loads of people got there.
While I realize that we didn't get to experience the whole of the hawaiian hospitality, or be there long enough to slow down and relax, it was long enough that we both fell in love with the islands, and can't wait to get back.
We did have a few days in Waikiki before the cruise, and wish we had done some after as well.