Excellent all the way around
You can't go wrong with the Aggressor fleet. The Palau Aggressor II takes you to more dive sites than you could ever do from a resort and if there's enough interest they can organize a land tour of Pelileu island. They can also organize a trip after your dive trip to jellyfish lake and rock islands. There is more free time on this trip than other liveaboards at the end. The food is fabulous and the divemasters know where to find all the things you came to see. There are usually 3 divemasters in the water with 2 groups of divers.