I would have to pick Kauai, but as pointed out, your island preference will really help drive your choice. Kauai is more quiet, relaxed, lush and natural. While Maui has more activity and is more "built up". I really think though that if you put the 2 facilities side by side anywhere in the world, the Kauai property just has more going for it. By the way the RC there is also fantastic- don't make dinner plans as you get a full meal there w/great wine/beer/drinks included gratis- similar to Maui but maybe a slight notch higher).