I love the Blue Hole trip (with Amigos del Mar). It's a long day, but always worth it to me. Keep in mind, whether the Blue Hole thrills you as it does me, or leaves you cold as it does some, there are two other fabulous Atoll dives as follow ups and lunch on an idyllic island. No matter where you stand, it's a pretty fantastic way to spend a day.
I go out to the Blue Hole on almost every one of my trips to Belize. Sometimes I go twice on the same trip, depending on the length of my stay. So far, every time, I've come out of the water after that dive saying again, again, I want to do it again!
The Blue Hole dive is not a "reef pretty dive". It is a bit dark, can be a bit murky, and due to the depth is a shorter dive BUT the stalactite formations are magnificent! Consider just the geologic history of the Hole, and from a diving perspective . . . you'll be diving where Jacque Cousteau went before you! And then too, there's the sharks!! Woohoo