We had a good charter experience with them (which may have just been lucky). We paid for a 40' cat. A week b/f our departure, Seth called and said the owner blew out one of the transmissions. So, they put us on a newer 43' cat.
Re: ASA schools. I would find a local ASA school. Get to know those instructors. Some state-side ASA instructors also do ASA lessons in the Caribbean (on charter boats from reputable outfits).
BTW, this thread is a bit old.