I had my TC-P65S2 for a year before selling it and the black levels were still great. The thing that drove me to sell that was the fluctuating blacks -- ugh, and get the VT30
The Black levels on the VT30 are a little better, and the with no fluctuating blacks or brightness, it's a solid tv with great black levels (65VT30). I haven't noticed any change in black levels, day, night (no lights on in the room).
I think paranoia has a good deal to do with SOME peoples' perception of black levels or poor image on a tv of any type -- the more you read, the more you look for. Sometimes, ignorance is bliss.