Some thoughts:
Buzz - Samsung plasmas always get the criticism for buzz, and I am actually pretty good at hearing buzz, always have been. Well, this set with a bright image on the screen and no sound in the room, cannot be heard at all. I was very surprised, it's actually the quietest plasma to date.
Real Black Filter - The reflection on this screen is the best ive ever seen. On the S2, at night in dark areas of the screen, I could usually make out a faint outline of my wife's reflection and her sitting area. Not bad by any means, but I could see it. Well, I paused this set in a fade to black last night and I cannot see anything at her position, so I gotta say they did something good with the RBF.
Black Level - It's very good IMO, and I think it's better than the S2 which measured 0.009 fL. Now is it a Kuro, of course not, but we are talking about a 64" $2700 plasma that does 3D
Video processing - It is by far the sharpest plasma Ive owned. Plasma has always had a more natural look, sometimes too noisy, but this set is very very clean. I was worried when some folks compared it to LCD, but it's not artificially sharp, just looks good. I also know Samsung has been pretty good with video processing for awhile, so I should not be surprised.
Floating blacks - Anyone that keeps up with the plasma wars at AVS might know of a Panasonic problem where in darker scenes, as something bright is introduced, you actually see the black level of the entire screen rise, kinda like bumping up the brightness control a little. Well, the 2011's have it and some have been saying the Samsungs now have it. I can confirm first hand it does. Reading patents at another site, in order to meet eco requirements the way these panels are driven tend to produce this annoying byproduct. When I first discovered on the S2 I was a little disgusted by it, but ive accepted it for what it is and don't want to let it ruin an otherwise great set.
Cinema Smooth Bug - The other con to this set. When you feed the set 1080p/24, you can turn CS on which is it's 96hz mode for proper 24hz handling, but there is a pretty decent black level rise while CS is engaged. Seeing the before and after, I'll be leaving it off, because 24hz only support has never been a huge jump for me, I prefer 24hz/60hz smoothing like LCD's do. When it comes to black level vs judder, Id rather have black level, and here are shots of it on and off.
Running slides right now while working and sleeping, then watching normal tv with contrast down rest of the time. I plan to rack about 150 hours on it, then calibrate next weekend. I highly expect the calibration to look beautiful because Samsung's CMS always works well, and they have a 10pt grayscale adjustment which means you can dial in gamma and grayscale at each step, instead of low and high.
