My opinion is that the snorkelling is much better at Coki Beach. However, yes, there are pot smoking Bob Marley types there. Coki Beach was very secluded compared to Sapphire. Sapphire had iguanas (large ones! arou d the beach area, Coki had a few chickens! Oh and renting items (chairs, floats, etc) is cheaper on Coki but the items are nicer, better maintain on Sapphire. I would bring your own snorkeling gear for sure!
Have a wonderful trip!