Installed this on an Asus P8P67 and the plug was a perfect fit in the motherboard, no trimming required.
Performance compared to the USB 2.0 reader I took out was fantastic. With a Lexar Professional 300x UDMA CF card I got a 16x speed up on reading and a 9x speed up on writing.
With Class 4 and 6 SDHC cards the speed ups were 5x on reading and 2x on writing.
The only downside I've noticed is that the CF slot is shallow, as others have said. It is really easy to insert the card misaligned - take care.