Sadly, you can tell that a lot of the reef closest to the shore has been damaged by human contact, and even with the crowd control measures in place I think they still allow too many people in the area at a time. We still were thrilled by our experience here, and think you should definitely put this on your must-see list when you visit Oahu.
Also, I totally recommend buying a Lifeproof case for your iPhone if you don't have an underwater digital camera. We picked one up the evening before for about $80 and we loved being able to take photos underwater.
More of our Hawaii Vacation: