I plan to take an open water course in Cairns, Australia in July. I know, from reading other threads, that the most important factor is the instructor, not the certifying organization (NAUI, PADI, or SSI). However, since I need to book a course prior to my arrival in Cairns, how do I know who is reputable? Obviously, each dive shop's web site lists rave reviews, but what else would they publish? I don't know how to choose.