I would have to say yes it is an official site to buy from. It is up to the buyer to check out the feedback of a seller and to ask questions before buying. I personally have made several purchases thru DHGATE with great success and have been very satisfied with the quality of the items. I have had one seller try to rip me off, but the good thing is DHGATE holds the money and does not release to the seller until you say you have received the item and are satisfied.
DHGATE refunded my money promptly.
Never pay the seller directly, always pay with paypal thru DHGATE and you can't lose.