We love Keoki's! During our last trip this is where we ate the most. The food, although not necessarily the best on the island, is really pretty darned good. They always have a good selection of fresh fish on the menu that is done in a variety of different ways. Consult your server for what's best on any given night. We prefer to eat in the bar/lounge area. It's simply cozier and more friendly. The dining room seems more formal, even though it's not.
We didn't once make reservations, but on one night the place got inundated by a convention from the Hyatt. We ended up waiting a bit for a table but it wasn't long (20 minutes, maybe?).
On some nights, weekends I think (but I was on vacation, it was all one long weekend), they have live music, usually some sort of Hawaiian music. Very pleasant indeed. Being that it's an open-air restaurant, the sound wasn't deafening and carried nicely.
We love Keoki's and will continue to go back.