What about Great Blue Hole?

I still vote Glovers but really enjoyed diving the Great Blue Hole - so unique! We were lucky to have loads of big reef sharks swimming in and out of the stalactites with us and part of the win was the 2 additional dive sites, Half Moon Caye Wall and Long Caye Aquarium.

look at the blue hole on youtube...some like holes and some dont.

night dive at Hol Chan Marine Reserve is a must do. Turtles, squid, the glow worm things, and all the animals come out to feed. It's not deep and has a tidal current but watching the green eel and parrot fish work together was cool. The eel poke thu all the holes in the reef, the parrot fish grabs an end and the eel comes out to grab the other end and the food frenzy is on! Ambergris is easiest and has the most sites with a few swim throughs.

The blue hole is basically a notch in your belt but it comes with Lighthouse and Glovers Reef so it's still good, though you're paying a lot for gas.

All the places mentioned so far are great dives. They are all part of what makes Belize a world-class scuba diving destination. As a matter of information, there are mainland locations for cenote diving, though they haven't been developed yet. I know of several in the Corozal District. Just a thought for an aspiring dive center owner.........
Greg

Blue Hole is different. Not much life down there except the sharks which circle on the edge of visibility in the middle. You have to go down to 30 m to see them and the stalactites so it's not a long dive. Careful going down though, I hit 40 m before I realised the beeping was my computer trying to tell me something.

The highlight of that trip however was The Elbow at the bottom of Turneffe Atoll. Amazing viz, saw a sailfish above us, got close up with a turtle, watched dolphins chasing each other, and good coral with all the small stuff that goes with it.

Gladden Split is all about whale sharks. You wander about in empty blue water for ages hoping to see one, and when you finally do it is as fleeting as it is amazing. The snorkellers up top got a better view I think but they also got seasick from the swell as it is outside the reef. The smart ones brought pills and took them on the way out.