I spent about four hours tonight with my brother's 51" F5300. I have to say I am really impressed.
I used the Spears and Munsil along with the AVS test patterns to calibrate basic settings. Movie mode, Warm 1, contrast at 90, brightness at 46, color and tint at default, sharpness at 3, and gamma -1. Cell light will vary to what you want or need. I turned off all of the gimmicky features and set the Black Optimizer to Dark Room.
The unit gives a very detailed, really crisp, bright natural image. Colors and grayscale out of the box looked good and natural. I was expecting just a bit better black levels, but the smaller size panels never seem to match what the larger sized panels produce, so it may vary.
Motion looked fine.
I looked closely for fluctuating brightness/pops with a variety of channels and Blu-ray (didn't check hockey) and I saw nothing. (I briefly had a 64D8000 before the firmware update and that was a nightmare for me).