As the OP seems to be familiar with the Caribbean, we'll move this over to the Hawaii forum for broader discussion.
dstan
AA Forum Co-Moderator
A few notes from someone who has been to both: 1) Expect Hawaii to be more expensive than many Caribbean destinations. 2) Agree with oopsz above, Oahu is my least favorite of the Hawaiian islands. 3) As you have Hyatt status, note that the Grand Hyatt Kauai is a very special resort, not to be missed, with a nice "lagoon" pool for the kids to hang out in, and the beach just beyond, and plenty of sites to see around the island. 4) Also plenty to do, see, or relax at on Maui and Hawaii (though the Kiluaea eruption may disrupt that last one currently).