Someone mentioned off-axis image degradation in LCD sets. The Panny 42 inch LED set I recently purchased (TCL42ET5) features their "IPS LED panel" and it does what it advertises - improves the off-axis image greatly. As I mentioned previously, I would prefer plasma over LCD/LED, but chose the LED for power consumption considerations, but no regrets to image quality yet. My only concern when I first turned it on was a somewhat dark picture, but I switched from Cinema to Standard mode, and the image brightened right up - pretty close or maybe even brighter than the CRT it replaced now.
The LED comes with a "Cinema smoother" feature which really does smooth out motion - so much so it was creepy ("soap opera" version of "The Mentalist"). I turned it to the low setting (not off), and I'm happy with that. I think it has four degrees of smoothing that can be selected via menu, the default being the highest setting (might make some people happy - just not me).
A corollary to most Panels being dispalyed at big box stores replete with Florescent Lights is that many folks are judging a Panel's performance by how bright the picture is. Manufacturers now have what many of us call a "torch mode" for Display Units.
Sadly, this mode could not possibly be any further from the Black Level, Color Temperature, etc that a ISF Calibrated or THX Calibrated Display honestly looks like. Moreover, these standards are in keeping with the way that both TV Broadcasts and Home Video are intended to be viewed. When the brightness and picture level are cranked up, it distorts dark scenes.
This is why the first thing I do. when I get a new TV is to use a Calibration Disc. Discs like Avia, Digital Video Essentials, Spears and Muncil all provide a myriad of Test Patterns for getting your display as close to Reference Level as possible. An ISF Calibrated Calibrator takes things to a much higher level by using very expensive and specialized equipment and going into the Service Menu (more often than not) to account for Greyscale and Color Decoder issues. Another great thing about ISF Calibrated Displays is that usually there are settings for Day and Night Mode.
All of this being said, many find a properly calibrated display to be somewhat dark owing to decades of using TV's that are so far off reference level. All the same, once acclimated to it, it drives me crazy to watch TV's in Torch Mode.