Deciding on which liveaboard requires some research. As has been mentioned amenities, food, accomadations, number of dives you can make etc. etc. Southwestern Carib. ?? Belize, Bay Islands or Cayman maybe?? Cayman would have to be the Aggressor, Bay Islands(Roatan) Aggressor again but Belize you have options, Peter Hughes, Aggressor or Nekton ( I think?). I've been on all but the Nekton. Several times. If this si your first liveaboard I'd take a good look at the Belize aggressor. The boat has received "best Liveaboard" several times. The diving is very good and very easy. Many direct flights to Belize city and a short drive to the boat. you'll dive on Glovers and or Turneffe and then spend most of your time on the southern end of Lighthouse reef. They usually do a beach picnic on Half Moon caye mid week. The runs between dive sites are very short and usually they move the boat while you are having bfast and lunch. Also as been mentioned and if you have time/$$$ you can hop over to Ambergris Caye for a few days for some pretty laid back land based fun-IE laying on the beach, racing golf carts, cocktails at sunset, etc. etc. If making 25 or so dives for the week yes youcan dive at Ambergris also Hit the web and you can find plenty of info or if you want you can ask for more specifics-Dive Safe-M