Even though it is a bit more expensive, I would go with this one: LG 43UD79-B. The Philips sounds like it has issues with prolonged image retention as well as general quality control issues. On paper it looks great though.
Second this. I got the LG 43UD79-B literally a week ago and I absolutely love it.
43" is the PERFECT screen size for 4K, anything smaller and you have to enable DPI scaling, which kind of defeats the purpose of a 4K monitor in terms of screen real estate.
For the price ($600-$700 depending where you live) this monitor has features other monitors twice the price do not have, e.g.; 5ms response time, Picture on Picture, multiple inputs so you can have up to 4 devices connected at the same time to the monitor and see all 4 outputs at 1080p side by side, audio input selection, etc.. It even has a VERY handy remote control.
It does have a couple of minor (IMO) issues others have also complained about: sometimes (like once a day, tops) the screen seems to lose signal and goes black for a fraction of a second. Puzzling but it happens too quickly and too rarely to become a real nuisance. There also is a kind of black 'Bermuda triangle' border around all four edges of the screen where the pixels that go into it cannot be seen if you are looking at the center of the monitor (but become perfectly visible if you move your face so you are staring straight at the edges - yes, the monitor is THAT big). Only ever noticed this as a problem because the 'black border' kind of gobbled up the right half of the vertical scroll bar of a maximized Firefox window.
You will need a BIG desk and a deep one too: this monitor is humongous (but you will quickly get used to its size).
This monitor does NOT support G-Sync or HDR (not surprising at all, given the low price). It does support Freesync, but the dynamic range is so small it might as well not.
Previously I was running 3 x 30" monitors at 2560x1600 each. The new 43" 4K monitor replaced the central 30", and I run into an issue I had never heard about until then, which you should be aware too if you are running Windows 7 and also have multiple high-resolution monitors (or plan on having):
The Desktop Window Manager (DWM) on Windows 7 uses a DirectX (DX) 10 texture to compose the Aero desktop. Textures in DX10 cannot be bigger than 8192x8192 pixels, and, because of this, the total height and width of your extended desktop area MUST NOT exceed this size or the DWM will crash and you will be thrown back to Basic, non-glass, non-hardware accelerated, mode - with no way to turn Aero and Glass back on.
I was running my previous three 30" monitors setup side by side, which resulted in a 3x2560 = 7680 pixel extended desktop. No problems there. When I replaced one of the 30" monitors with the new 4K monitor, the width of the extended desktop became 2560 + 3840 + 2560 = 8960 pixels, which is larger than the 8192 limit.
Even the built-in Windows 7 Microsoft Aero troubleshooter will NOT tell you this is a problem, instead claiming that no problems were found and that Aero should function correctly (but it doesn't, and any and all Windows settings related to it will have mysteriously disappeared). It took me some time and a lot of Google searching to figure out the true cause of the problem.
There is no solution on Windows 7 other than to either reduce the resolution of one of the monitors or position them in such a way that the total height and width of the extended desktop does not exceed the 8192 pixel limit.
Windows 8 and Windows 10 do not suffer from this limitation (until 8K monitors become the norm, ahah!) because they use DX11, which doubles the maximum texture size to 16384.
