I took a trip a few years ago to Hawaii and stayed 3 nights each at Shearwater and Bali Hai. As has been said, Shearwater has awesome views, costs more points, and is harder to get.
I would choose Shearwater if you love the sound of the ocean, as you can leave your patio open and hear the waves all night long. Also, if you are going to spend a lot of time in your resort, especially sitting on your patio in the morning/evening (like we did) Shearwater should be a priority. Bali Hai has small patios/garden views, but it is so much different from the ocean view.
If you are just using your room as a place to sleep and plan on spending all of your time away from the resort doing other things, I would save the money and go with Bali Hai.