When we were last at Aulani, they didn't have a luau, I think that's new! The Aulani Starlit Hui show is not a regular luau. They don't serve food and drinksat that show, it is all entertainment. It's been a couple of years since we were there.
We went to the Paradise Cove luau on a previous visit and found it to be very "cheesy" in comparison to the awesome luau we attended on Maui before that. The food was "meh". However, if you've never been to Hawaii and want to experience a luau, see if the Ko Olina Marriott is having theirs, the Fia Fia, during your stay. I've read that it's one of the best on Oahu, but it used to only happen on Tuesday nights. It's only two lagoons down from the Aulani and it's a lovely walk on the beach path to get there.
Either way, you should attend Starlit Hui because it is complimentary with your Aulani stay. Arrive early for their fun activities!
Best of luck!