I've chartered in all of the places you're considering, and would offer an additional thought: the Abacos (Bahamas). Beautiful sailing, amazing clear waters, stunning beaches, and charming settlements. The area is well charted, with a cruising guide which is updated every year, so the sailing is easy. You anchor in firm sand, and you can see your anchor as you drop it. The entire region is geared to boaters/sailors, as that is how the islanders get around, as well as many visitors (even land-based ones). The Abacos may not have the yachtie party scene of the BVI, but there are plenty of beach bars and restaurants where you can find activity. You can get there via Miami (MIA) to Marsh Harbour (MHH). Moorings/Sunsail are there, as are a few local charter companies -- with plenty of catamarans from which to choose.