Consistent 1080p streaming has returned for me.
Some of you shared that you called Netflix and had them de-authorize your Apple TV. Afterwards, you re-authorized the device and it restored video quality. I, too, called and requested the same; however, the agent seemed confused by the request. Instead, he instructed me to reboot my Apple TV but not through the device's Settings. Rather he had me press and hold the remote's down button and menu button simultaneously. This restarted the Apple TV. He claimed this reset the device differently. Unfortunately, when I played a Super HD feature afterwards, the video quality had not improved. He made the ridiculous claim that the video stream would ramp up with time, as if that were the normal experience. It did not.
Before we hung up, he recommended I change my Playback Preferences from High Quality to Medium Quality, believing that my 30mbps bandwidth speed was somehow too fast for Netflix's stream. I've heard a similar explanation given to a friend who was having issues with Mail because of his ultra fast FiOS broadband service. Still, the suggestion seemed unplausible. Nevertheless, I was about to test his advice when I noticed the following playback preference: 'Prefer HTML5 player to Silverlight'. I unchecked its radio button. Immediately after, video quality was restored to Super HD features. It has been reliable for the three days since. Is it coincidence or is the player preference somehow affecting the Apple TV?