Watch out for hidden costs - I did my PPL at OBA at the beginning of the year and didn't pay any surcharges; I met a few guys who were learning at one of the schools you mentioned and they were paying $7 an hour fuel surcharge (met them when I went for my CAA medical in Florida.. very cheap it was, too).
I agree about a 3-week PPL being almost impossible at this time of year in Florida, though October is usually very good. Get your exams done before you go, otherwise it'll be a very hard slog!
Good luck