They're not listed as official reseller and in their menu they spell "Terms and Conidtions".
For what it's worth, they just ripped me off. Here's a link to a reddit thread where I posted the whole saga (jlh2112) http://www.reddit.com/r/BitcoinMining/comments/1rmkaw/minersourcenet_legit/
Basically I ordered three things from them (2 pre-order, 1 in-stock) and then heard nothing. After a bunch of follow-up attempts they claimed they shipped my AntMiner, but never gave me a tracking number or anything. After about two weeks and a bunch of unanswered emails later, I hadn't received the AntMiner and noticed that my account had been deleted from their website. I posted the whole thing on reddit and finally got a response (all responses I've received have been one line emails that didn't answer my questions in full). They ended up cancelling my order and refunding about half of my Bitcoins. Now my emails are going unanswered again. Unfortunately it seems that with Bitcoin I don't have much recourse here; at least if I had paid with my credit card (not an option) I could just let my bank know that I never received the goods. I really want an X3, but I just can't risk losing more money.