Widescreen monitor, UltraHD | 4k?

Question

Monitors

Hello, it's time for a nice update.
Stuck with the choice of a new monitor from the category (widescreen).

In general, the task is to get out of my "square" 19 ". I'm looking in the direction of specifically non-standard proportions. More working space on the screen is required. Not in graphics, not with crazy color reproduction. Just like 2 monitors only without frames between them)

the budget is around $ 500 1.

I really liked the Samsung U28D590D variant
Based on the reviews, this question arose. Many complain about the buggy. Quite often they write that the GTX670 without SLI will not pull in tandem. They say ati and 1 is enough card.
I have a GTX650, when I took it, I didn’t even count for use, so to speak, "as intended. " Actually, is this card enough for 4k resolution?
If not, well, or - not enough, then is there any point in 3840x2160 pix.? Many comment that even on it 2560x1440 is enough. (Let me remind you, the task is not to drive movies, but to have several windows conveniently located. Full vision coverage is not necessary, because it’s much better anyway than swapping windows to fly like crazy)
2. Monitor 29 "LG 29UM65-W gl.White and Monitor 29" ASUS PB298Q Black
Similarly, based on the first point, is it necessary, but whether 3840x2160, for the most part from the technical side. Or such options will be better both in terms of the moment with the video card, and in general in working with them.

Or even forget about it, buy yourself a TV and choke on vague text?))

General opinions in the monitor sphere are generally interesting, because I understand them "on the way".

ps Of course I agree with the option: "Go and see." But before the holidays you can’t find a free mintuk at all (