The models improve a little every year. For the "C" models, this year the 8000 Series offers 3D, a darker black filter (for better dynamic contrast ratio) and Motion Judder control to improve the smoothness of the picture. There's also an additional calibration mode if you decide to have your set calibrated.

Also, the PN50C8000 also comes with Samsung Apps, which is a whole new offering of widgets and additional features. You can check those out here:

Does that help answer? If you have more questions, I'll be happy to assist.