Nudibranches, Sea Slugs, and other Crustaceans; loads of Moray eels. Site was teeming with sea turtles--lots of hawksbills (apparently very rare--a lot of them were quite old); they were very friendly (one was about seven inches from my face as I was hovering), and we were lucky enough to see one at a cleaning station surrounded by fish. Also had the opportunity to swim through a cave-like rock tunnel, in which we saw two 4'-5' long White-tip reef sharks as well as a lot of larger Angelfish, etc. The dive became even more excited when a pod of whales passed through (late in the season) and began to sing; fairly certain that the same pod surfaced later as we were heading back to the docks.
Negative--Ear was very painful as I got water in it--had to go up and equalize several times
Positives--Balanced out my buoyancy to enable hovering; very good on air consumption--didn't use much