I bought a GMT II (not the very new one which I own as well) in August in Chow Tai !!!!, 29 Queen's road Central for 33,435 HKD which includes the 10% discount every dealer gives on this type of watch. I was pleased dealing with them. They run several stores on HK island and Kowloon and even one in the airport -> very reputable house. By the way, I do not know of Dubai prices lately but weakness of the dollar (US or HK = same), the mountains of choice and no taxes make HK a top place to buy watches even second hand ones...