We just spent a week at Ko Olina on Oahu and really enjoyed our stay. We used points, 100K for 7 days in a deluxe room, no view. Its a time share, so you can spend more points or money for the full villa, which is a 2 bedroom with full kitchen or take a deluxe room, which has a king bed, fold out sofa and a kitchenette. We really enjoyed the grounds and the pool areas, which are extensive. The main negative is the distance between the resort and Honolulu, where we like to shop & dine.

After Oahu, we visited the Big Island for a couple days and stayed at the Waikaloa Marriott. The rooms have been remodeled, but we didn't care for the beach. It has huge dunes build up to prevent erosion (I presume), but it makes it impossible to enjoy sitting on lounges and makes the view ugly. The good thing is you can easily walk to Kings center for dining & shopping. We ended up driving down to Hapuna State beach. Much better, IMO.