Just mounted a FSA Control Center on my K-Wings. Very secure, as long as you torque the bolts to spec it's not moving anywhere. The mounting arm is plastic so overtorquing will probably not damage the bars anyway. Got a Garmin Edge 500 mounted on it with no issues. I like it because I can change the viewing angle of the Garmin versus when it was mounted on the stem.

$14 brand new in the package on eBay.