To be precise it is not card reader but the thing with audio ports. Still it is very flexible and I see no side effects :]. However I would not buy this card now because of poor support for 3d acceleration under linux.
I noticed some issues with USB controller/drivers or USB power. I have wireless keyboard which loses time to time some letters. Strange thing is that the keyboard works perfectly under linux.
Sometimes also my mp3 player does not want to charge over USB.
Have you experienced any issues with usb?