You can get a similar experience to Tubataha on a day trip in the Maldives and perhaps (I haven't been but have been told) Palau. I just got back from a trip that started in Dauin/Apo and ended in Malapascua/Gato. To oversimplify it, do you want to get close to Threshers? They are incredibly shy, saw a thresher about 100' away in the Maldives, and started heading for it, probably still 90' away which was when the thresher noticed us coming and darted away not to be seen again. Malapascua is the best place on earth to get close to threshers, one got about two meters from my camera. With Malapascua, you can see tigers, mandarin fish, and snorkel with baby blacktip reef sharks. Reliably diving CLOSE to Threshers is exclusive to Malapascua and you have extremely high odds you will see Mandarin fish and baby blacktips