One advantage of the Blue Hole trip is that you can be absolutely certain you went to the Blue Hole.
The last time I was in at Ambergris, I was leading a trip for the shop for which I worked. When I arrived, someone who had spent the previous week there gave me a warning about the operator we were using. He said the day they had scheduled their trip to the elbow at Turneffe was the day after some local holiday. When they arrived for their trip in the predawn darkness, there was no one there. Eventually they learned that the problem was that everyone who worked for that operator had been out celebrating until the wee hours. They finally found a crew and left more than an hour late. Their DM slept the whole way to the elbow. They did their dives and returned, getting back more than an hour earlier than scheduled. On the way back, the diver pointed to landmarks and finally got the DM to admit that they had not gone to the elbow. The DM said they had gone to the "little elbow."
When my group did our trip to the elbow, we, too, arrived in the predawn darkness to find no one there. Eventually, we, too, left an hour late. We did our dives at a site that I thought was pretty unremarkable--certainly not worth the extra money we paid for the trip. Like a total idiot, I forgot about my warning and spent the return trip chatting with the people in our group, not paying attention to the return trip. I was thus surprised when we got back more than an hour earlier than scheduled. Of course, I had no way of proving that we had not gone to the site for which we had paid the extra cash, no matter how hard I tried.
The operator we used is no longer in business, but I assume everyone who worked for them found work with other operations and is still on the island somewhere.