Well, I'd have to say I was one of those folks that had been following this thread since day one, tracking the shipments of TV's before they were for sale, and had super high hopes for this TV.
My 55 inch P arrived yesterday and here are my impressions, sad to say I'm a bit disappointed. I am by no means a professional and set the TV up with Buzzard's calibration settings on the first page.
PROS in my opinion:
1080p upscaling was my biggest fear, and I must say compared with my 2013 M, this TV looks great and I think they did a great job with upscaling. It is mounted above my desk and as close as I sit, the 4k is very noticeable to me. On a regular 1080p set of this size, I can definitely see individual pixels. On this TV I cannot.
After using Buzzard's settings, I must say the colors look incredibly accurate.
Screen uniformity is EXCELLENT on my set. I had some minor banding and noticed that there were screws on the backside of the TV exactly where the bands were. I took it off the wall, slightly loosened the screws (they are still really tight) and noticed the banding went away.
In anything but a completely dark room, I really can't notice anything wrong with picture quality in general.
The viewing angle is great. It is mounted above my desk and my bed is to the side. In bed I'm viewing from about a 55 degree angle and colors remain accurate on this IPS panel. (more on contrast in the cons)
Remote response is good, the addition of QWERTY is awesome.
CONS in my opinion
I'm running a Kepler based Nvidia card (a GTX650Ti) and the R340.57 drivers which should support 4k @ 60fps at reduced Chroma. Unfortunately the bad news here - after playing with this for a day I have been unable to run at anything better than 4K @ 30FPS ALSO WITH REDUCED CHROMA. Considering I'm planning to use this for desktop use almost more than as a TV, this is a HUGE bummer in my book. I haven't given up on it yet, as I may try another card and HDMI cable, but I will say, if I can't get this resolved, or at least be able to run 4K at 30Hz with full Chroma, I will be returning this TV.
While the off angle viewing of the IPS panel is great as far as colors and detail are concerned, the already somewhat compromised black levels get progressively worse as you move away. This TV's 64 local dimming zones are great, the algorithms that run them are pretty good, but with the off angle IPS glow, local dimming is just far too noticeable when viewing at severe off angles.
The front side of the remote is not backlit. Why would they leave this out? I use the front more than the QWERTY. Not a huge deal as I can ebay an XRT-510 non qwerty remote that has a backlit front face for next to nothing.
The box and packaging were great as far as unboxing it easily, but the box and protection for the TV are so slim I can understand why so many folks got damaged TV's. I just got lucky with mine I guess.
Other than the HUGE HDMI dealbreaker for me, this is a great TV with excellent picture quality in my opinion. If I could run 4K at 60hz and full chroma, I would take it off the wall, sell my computer monitors, put it on my desk, then just swivel it to point directly at me when in bed which would eliminate my off angle IPS glow and local dimming issues. Unfortunately, with no full chroma and limited to 30Hz, I can't justify getting rid of my monitors and putting this on the desk.