My family and I really enjoyed it, though we went in with pretty low expectations (I had no idea how big and well-organized it was, I was under the impression it would just be a few Polynesian arts and crafts, exhibits and such). I'd recommend only spending a day there, though be sure to arrive plenty early, as you will need 5-6 hours to do everything.
Also, do the luau. We went with the Hawaiian luau, but I hear all of them are great, and it was a great experience. Plenty of entertainment and delicious food.