Gray says all there is to say about the PCI-Express 4-Port USB 3.0 Expansion Card sold by PC Trading.
Definitely be careful about plugging in the power connector, a step missing in the instructions for "Hardware Installation". It might be safer to plug in the power connector before you insert the card in the PCI-e slot. And before buying check that you have one of those old-style 4-pin connectors, the sort used on old pre-SATA hard drives. If not, they cost next to nothing.
The card's fixing to the bracket is also a bit flimsy. But that should not be a problem when installed.
Drivers installed just fine. Like Gray, I suspect, I did this from Device Manager, pointing it at the CD, rather than by running the setup routine as suggested in the instructions.
Windows 7 (64-bit) also found an updated driver after being told to go and look.