The shark dive was one of the coolest things I've done here on Oahu. Being able to experience these creatures in their natural environment was incredible. Not to mention, the early morning views of Mt. Kaala and the North Shore from a few miles off coast were gorgeous. The boat's crew, Noah and Captain Grizzle, were great. Really friendly and welcoming.
The only thing that would have made my experience better would be NOT getting sea sick. Other than that it was such an awesome adventure.
Couple of tips:
1) If you're on vacation, schedule your tour toward the beginning of your trip. Our initial excursion was cancelled due to rough ocean conditions, so unfortunately many of the tourists in that group missed out on this cool opportunity because they were leaving the following day.
2) Take Dramamine. Sea sickness is real!!! Don't let that ruin your experience.
3) Use the bathroom before you leave. There is no bathroom on the boat so you don't want to have to hold it for an hour and a half. Also, the nearest restroom is a typical beach bathroom with no doors on the toilet stalls, so you may want to find another public restroom nearby if privacy is an issue for you.