Above product is sold out...
I would say get the Zebronics model. It has VLI800 chipset which is more or less similar performing compared to the ageing NEC chipset. Also there are both 32/64 bit Win 8 drivers available on the VIA website for the card. You will also get 1 year local warranty.
I am yet to see an Etron chip based USB 3.0 card which is suppose to be the fastest.
DX can still be used for non electronic cheap components like cables, converters & other PC accessories, though I would avoid it for addon cards which are liable to get damage in transit.I would also re-iterate that my experience with them is fulfilling till now. Received one of my packages from them last week. Delayed but delivered. Others may not agree based on their experience...
Summary of PCI Express Interface Parameters:
Base Clock Speed: PCIe 3.0 = 8.0GHz, PCIe 2.0 = 5.0GHz, PCIe 1.1 = 2.5GHz
Data Rate: PCIe 3.0 = 1000MB/s, PCIe 2.0 = 500MB/s, PCIe 1.1 = 250MB/s
Total Bandwidth: (x16 link): PCIe 3.0 = 32GB/s, PCIe 2.0 = 16GB/s, PCIe 1.1 = 8GB/s
Data Transfer Rate: PCIe 3.0 = 8.0GT/s, PCIe 2.0= 5.0GT/s, PCIe 1.1 = 2.5GT/s