I bought my 64D7000 in mid-May 2011 so it's been eight months.
I find the TV just fine. Some are bothered by brightness pops but this phenomenon appears to be most obvious when Cell, Contrast, Brightness, and Gamma are set high. Since I prefer a relatively dim (realistic ) picture, I rarely see the pops -- and I mean almost never.
For those technically minded, my definition of dim is a peak white output level of about 27 to 29 ftL.