The native scaler for the ATSC tuner kinda sucks. The picture is soft and the color palette is crushed. Using the Hauppauge tuner on my computer along with mplayer produces a far better picture. For a device that's sold as a TV, you would expect better.
Loaded the 50" firmware on my 39". Reset my graphics card profile and settings and recalibrated. I took my time and set by black point and white point carefully.
Much much better, BUT... the problem with gradients is still there. Viewing http://www.lagom.nl/lcd-test/gradient.php clearly...
I hooked up the VGA port and displayed the image without the crush of pallet. The problem is along the HDMI path. Graphics card/driver, cable, or monitor.