@mgdesert, I've only done trips to Huracan so I don't have much to offer regarding Caye Caulker or San Pedro. I will mention that if you're interested in the Blue Hole, the experience won't be as good as what you get with Huracan or Itza. By being located near the Blue Hole, they get you in before the other boats arrive. Once you've got multiple boats on site (pretty much daily), there are a ton of divers are kicking sediment into the hole reducing viz. When you get there early with a small group, it's pretty spectacular. As @d^2b, mentioned, they do lack AC and there's no town to walk around and do things, like you have in San Pedro. So not everyone's cup of tea.