Firstly I e-mailed to Beachcamera (the authorized dealer) for asking about the cheaper price (399US) that I found in Buydig and they reply to me that they can match the 399US for me but I have to call directly to his sales manager, unfortunately I stay outside US so I can not.
Then I e-mailed to Buydig for asking detail about warranty and they reply to me "This item is brand new and is supplied with a 1 year warranty".
Funny is both Beachcamera & Buydig replied me by the same sales manager so I thought they should be the same company and also the item.
FWIW, I'm not aware of any of the ATH-W series (ESW9 excluded) being faked, but my understanding is that AT will only honor warranties with an SO originating from a listed authorized dealer. You can read more about it from AT:
http://www.audio-technica.com/cgi-bin/warranty/search.pl
Select Audio-Technica brand products purchased in the U.S.A. from an authorized Audio-Technica (A.T.U.S.) dealer are warranted for two years from date of purchase by A.T.U.S. to be free of defects in materials and workmanship. In event of a defect, End-User’s exclusive remedy is at A.T.U.S.’ election, the cost of repair, refund of the purchase price in the form of credit or cash, or replacement of the product. The product must be delivered to A.T.U.S. or an Authorized Service Center, prepaid, together with the sales slip or other proof of purchase date. This warranty excludes defects due to normal wear, abuse, shipping damage, or failure to use product in accordance with instructions. This warranty is void in the event of unauthorized repair or modification, or removal or defacing of the product labeling.
W1000X should carry a 2-year warranty, and you would have to present the original invoice from an appropriate dealer to receive service from AT (I'm not sure if they'll refuse all service/work-orders without a legitimate SO, I know that some manufacturers will, but I'm not sure if AT is that picky).
And more about their Unauth policy: http://www.audio-technica.com/cms/features/49ef9d703e98ba93/index.html
If you have doubts about the authenticity of an online reseller, please contact Audio-Technica directly at salespolicies@atus.com
And auth'd dealers list: http://www.audio-technica.com/cms/site/1e22eec97c088a8b/index.html
Buydig does not appear.
Were it me, I'd either contact AT and inquire with them directly, or (if they either say it's a no-go, or don't reply quickly, etc) try and return the product and go through an authorized dealer, simply to ensure that your warranty is valid. That having been said, there isn't *a lot* that can go wrong with these that would really be covered under warranty (any damage you do is on you; so basically the driver or wiring has to spontaneously fail of its own accord in order for the warranty to really matter - there aren't any active electronics in there, so they should be quite reliable), assuming the warranty is something you're worried about. I'm very skeptical that fake ATH-W exist, and you likely have a legitimate example - however, you may have a grey-market example at that (I remember a while ago the dealer you bought them from was selling "refurbs" on ebay with no packaging/UPC/etc for fairly low prices - that's kind of shifty behavior imho).
If you do e-mail AT and get more info on this, it'd be quite helpful if you could post your reply back here.