The most impressing fact for me in the Philippines are the people. I haven't seen any other country in the world where the people are as friendly as here. And even if they do not want to sell you anything ! Regarding safety, I never felt uncomfortable.
The diving is very good for Macro. For pelagics Tubbataha is the only place to see something unusual big. But you have to be there at the right time and current. The waves can be heavy as well. So it can be a lottery some time.
Two negative things I have to mention. The Sex Tourism is very common. If you see 60year old man with girls roughly 20, it is something that is more than a little bit weird. for the Filipinos this is not as disturbing as for us Westerners. How this fits with their Catholicism is an unsolved mystery to me.
The second is the non obeying to rules and the resulting environmental destruction. They do everything: Dynamite-Fishing, Cyanide-Fishing, Fishing with Bleach, Shark Finning and so on and on. You can justify all of this with the poverty of the people, but this doesn't make it any better. Even in "Ecotourism Hotspots" the rules are not worth the paper written on. Without enforcement there is no point setting rules in places like the Philippines.