Hi There. I have an 47 F8000 and had both 50in ST50 and VT65. They both have stunning black performace that is miles better than the F8000 in dark room viewing. The blacks bars on a movie are almost perfect black.
There are trade offs:
The f8000 is far better for viewing with ambinent light. In such conditions the blacks on the f8000 are more or less just as good as the plasma.
The f8000 you can sit much close to it. I view it from only 180cm.
The f8000 has a much better quality 3D, much better depth and pop. And the 3D clarity and sharpness and detail is far better. The panosonic plasmas 3D looks very lacking in terms of clarity, depth and sharpness, infact the picture always looks overly soft even with the sharpness set to 100%. They both have the same xtalk.
I kept the f8000 simply becuase its better for bright viewing and for its far superiour 3D.
Both panasonics movie in dark room performance is excellent. However they have huge amounts of dithering... So bad that i dont recommend them if you plan to view within 200cm of the screen.
If you dont care for gaming lag, then i would say try the samsung F8500 plasma. Blacks almost as good as pano, but with less dithering, brighter saytime picture and far better 3D (sharp, bright, less xtalk). I would have got the f8500 but its not good for serious gamers.