DH & I have been to the Luau twice, and loved it the first time and hated it the second.... hopefully some of these suggestions will help.
There have been 2 seatings in the past, hopefully that will continue. We went as a group of 6 to a late seating, the first time (when we loved it). There was a more mature crowd (in retrospect) and the darkness added to the mystique. The waitress seemed relaxed and gracious - very good. With a party of 6, we had a section of table to ourselves and it felt a bit private. This was in '97, and we enjoyed it so much we wanted to experience it again for our 25th anniversary.
So, the second time, we chose an early seating so we'd have time to so something else afterward. BIG MISTAKE for us - as a party of 2 adults, we were nestled in between other large family groups with little children, and the family on one side was completely miserable, whining at the waitress when she was near and whining about her when she was gone. The atmosphere reminded me of a school cafeteria. Had we been there with young children, we would have been fine, but going with an adult mindset and recollections of a very different experience, we were dissappointed.
The food looked good the 2nd time, but with the neighboring child coughing open-mouthed on our food, we didn't eat much. We "snuck" out before dessert. The show appeared to have all the same performers as the first time, but many of them looked like they had stopped working out and taken up beer drinking.
Anyway, our dissappointment was circumstantial, but definitely consider the makeup of your party when deciding which show to attend.
Have fun!