I really like this TV, i really do. However, there is another bug (besides it turning off randomly that one time while streaming netflix from my ps3):
If you have "game mode" enabled, and you play god of war 3, the screen will flash to black for a second, randomly, after a while of gameplay. If you turn off game mode, it never happens. (so it is the TV, not the PS3)
As far as I can tell, "game mode" just disables smooth motion. I turn that off when I'm gaming anyway. I have noticed no lag with game mode off or on.
When I called tech support yesterday (they are open saturdays) they were really no help. The lady on the phone didn't even know anything about the TV. When she talked to "level 3" support for me, regarding the "game mode" screen flash problem, she explained it to them incorrectly and they thought I was talking about the screen flash that happens when you turn game mode on or off (which is actually smooth motion just turning on or off - you can prove this to yourself by turning off smooth motion and then toggling game mode - there will be no initial flash). The problem is random screen flashes (no loss of audio) with game mode enabled, with god of war 3 (a graphics intensive game). I suspect this has to do with a bandwidth issue manifesting when game mode is enabled. I have swapped HDMI cables but that is not the problem.
The tech support rep had me reset the TV as a precautionary measure for the random turning off that happened once, and said that I should reset it like that if it flashes in game mode again. Well, I hadn't been using game mode because it obviously causes the flashing problem, so I enabled it today when playing god of war 3, and screen flashes happened a couple of minutes later.
In summary, Vizio tech support knows nothing. Also, they tried to tell me my firmware should be the most recent one for the 553. Right. Different TV, moron.
90 day costco return policy and 3 year warranty - I have a feeling I'll be using one of them unless it never turns off by itself again... (fingers crossed)