Sigma 120-300 OS - Hong Kong suppier OK?

I found the new OS version of the Sigma 120-300mm f2.8 zoom at AC Electronic Limited in Hong Kong:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230658110937&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en

Price is pretty good. Does anyone have any experience with them? Any disadvantage for a US buyer buying from them instead of a US supplier?

Thanks!
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Tom S.