I'm not sure what version of the ATC2K and ATC3K cameras you guys are using but I've never had trouble with the rolling shutter effect, and I can read license plates about half the time. It's not the best quality camera to be sure, but it mounts incredibly easy and it is relatively low profile on the helmet, at least compared to the gopro. The countour hd is a great camera from everything I've seen and heard but for the money I don't think you can beat the reliability and ease of use of the OS cameras, but hey to each his own and the more cameras on the roads capturing idiot drivers the better we all are.
Good Luck
Jeff