I have experienced and reported back in TJC general slowness of the dialer UI. Specifically, if I press the hang button once it is almost certain that the call will not be hung up, and no feedback will be provided, be it visual, aural or haptical. When hanging up, I usually press the button several times in a row to be sure to succeed. Unfortunately, sometimes this causes me to press on the just appeared “Call again” button - which will let a call start before the hang up button can respond to my subsequent frenetic presses.