Ive been twice. Neither time I remember great detail about where we stayed etc but I remember such beautiful beaches and really friendly people.
I remember a beach with huuuuuuge waves that we saw on one of the tours we took. It was amazing!!
You will have a great time no matter which island you choose :) we stayed on the main island somewhere close to waikiki beach. That was the beach we swam at the most but watch your legs. I remember huge barnacle covered rocks under the water :)