We stayed at BIBR down the beach a few years back and did the dolphin dive with AKR. They seemed to have a well run organization then, and I haven't seen any comments to the contrary by anybody recently. The only thing I am a bit hesitant about was that it appeared that the boats were very crowded when we went, but it was also the week before easter, so that might have been the cause.
If you are flying TACA (take a chance airlines) carry all your essentials in a carryon. They have a very well established pattern of losing baggage for a few days especially heavy dive bags on the flight that changes planes in Belize. Be aware that they can be pretty harsh about your carryon too, so try to keep it relatively small...They tried to take mine away that had regs and such in it. When i told them I needed some of the stuff in them, the helpful flight attendant offered a plastic bag...when she saw how much I was putting in it, she offered me a second one, so I emptied the entire bag into two of theirs and walked on the plane. Note sure exactly how that saved space, but it got her off my back.
Hope that helps...Good luck and hope to cya there!
AggieDiver