Yes... many have bought from there before... and some do mass orders from HK as well. Search the Consumer Corner and you can find more discussions on it.
I guess the one thing you may want to watch out for when you buy in HK is that you want a lens with international warranty, and to get a receipt from the shop too... so if something goes wrong with the lens, the international warranty is honored here in Singapore. There are grey sets in HK as well.