I've been using Aussie Gold Orchid Mix for just over a year, and can report wonderful results here in Southern California. There's some interesting chat on gardenweb.com about it too. I'm not sure if it's available outside the US but it's been available here for a while (in fact it's made in San Diego). My orchids have never looked better - great roots, new growths all over the place and this year I had the best blooms I have ever had. They seemed to last longer too, but that may have been my imagination!
Elizabeth