I decided on Donsol and Ticao to snorkel and dive with whalesharks because an ethical option was important to me - so skipping Oslob was an automatic for me based on what I had read and heard.
That being said, I wasn't a big fan of the BIO experience in Donsol (Butanding Interaction). They talk the good talk about conservation and protecting the animals but then they allow up to 30 boats (with motors on pretty much the whole time) to race around the bay for 3 hours, twice a day with up to 6 tourists on each. That's up to 360 people a day trying to get into the water with the WS. If there are only a few there you can imagine the potential for harassment and molestation, not to mention the sound of the motors alone. How this may impact their feeding and natural behaviour I don't know - but I was frankly quite disturbed by how many people there were there and I was there on a grey and rainy day when only 15 boats were out.
I should also mention that if you want to do Manta Bowl diving from Donsol, that tends to make for a long day with potentially bumpy conditions. It is a 1-1.5 hours boat ride each way to the sites and in the surface interval your boat may be stuck out there (without any shelter from rain or sun) or if they have a relationship with the resort, they may park up on the beach at the Ticao Resort. Inclement weather may also lead to dive cancellations as the water could be too rough for boats to go out and stay out there - even in dry season this seems to be happening more often. So something to consider. I stayed 4 days at the Ticao Island resort which is only a 20-30 minute boat ride out to Manta Bowl. If you stay there you can do up to 4 dives a day, 2 in the AM, 2 in the PM (the boat generally returns back to the resort halfway through to change tanks but they do make a wonderful bag lunch for you which had some really fantastic food to offer - highly recommend the Bicol express and pork adobo). We had quite a few cancelled dives when I was there at the end of March (2018) which was really disappointing. When we DID get into the water at manta bowl, it was quite amazing though - really huge whale sharks, though we did not see any mantas while there.
All of that being said, in my somewhat limited experience diving in the Philippines (I did Ticao, Malapascua, Coron and Tubba), Tubbataha is by far the best IMHO. We had 1-2 whale sharks on most of our dives out there not to mention the hundreds of reef sharks, hammerheads, mantas and the wonderful reef which had warm, clear water, healthy corals and just a huge abundance and diversity of fish, critters and so on. Unfortunately the season doesn't start until end of March - but something to keep in mind if you really want to have intimate, respectful (and sometimes lengthy) interactions with whale sharks while diving.
