Casts are the most important element to me. I once went through and added up all of the entertaining characters in every cast and it mirrored my season ranking exactly (with the exception of the ASS retreads). So, best casts were Borneo, Australian Outback, Pearl Islands, Amazon, Marquesas & China. Worst were Vanuatu, Fiji, Thailand & Africa. I think Heidik & Helen and Ethan/Lex were the sole point earners for their seasons.