They look pretty trustworthy, although i would recommend gamebygame.com Fast Shipping, Free shipping and pretty decent prices. $24 for a authentic acekard.
There are lots of websites that you would rather buy.
If you don't care about the price you could buy it in Realhotstuff fast shipping only for $24. If you care about the price get it from 0shippingzone.com they sell it for $14 and have faster shipping than DX.
Dont buy from Leetmod, I ordered from there back in April and customs still has my acekard 2i, and customer service never responded my emails or refunded my money, order from deal extreme, i find it much more reliable