I’m equally frustrated with the X20 mouse wheel.
 
Despite my best efforts, it remains unresponsive unless I apply side pressure—a patchy and annoying workaround. After purchasing another one, I processed an RMA on the first bad mouse, which resulted in a replacement. Since the second one I purchased is now bad as well, I need to switch to the one I received in from the RMA. Unfortunately, my expectations are low. If this replacement fails as well, I will be forced to give up on EVGA mice entirely.