Dive vacation on Hawaii or Maui?

My wife and I are new divers (PADI adv training, 30 dives) who are stopping off in Hawaii on our way back to the Philippines from the US in early April.

I'm getting the idea from research and other forums that the choice between Kona coast and Maui is a pretty much of a tossup, they're both good diving.

Are there significant differences in the fish and sharks we might see (other than Mantas at Kona)? Are there differences are in the sorts of corals or other animals we might see? Any big differences in the topography that might matter?

What are everybody's favorite dive sites?

Thank you in advance for your help.

Regards,
Bob

Bob, I dove Maui at the Molokini crater and there just wasn't much to see, it was corals and fish, no inverts, no sot corals, no big animals, etc.