Philips have an upcoming 40" VA-based UHD display. I was quite impressed with what I saw of it at IFA.
I personally wouldn't bother with 4k for a long while, even 2 newer cards will give you a low minimum fps in quite a few titles.. averages might be half decent but they will drop a lot more when action is going on.
There's some decently priced 4k monitors around now especially compared to the 1440p ROG Swift, but then you have to compromise with lower fps and no extra features and 60hz.
I'd prefer to go 1440p max, but will probably still stick to 1080p for a while yet.
Really just depends if you prefer a bit sharper image, or faster performance.. i'd prefer to get high stable frames tbh.
The jump up to 1440p for me from 1080p was ridiculous and mind blowing, let alone 4K which I've experienced a few times now. There really is nothing quite like it, but obviously I haven't had the benefit of 120 or 144hz gaming, which may be equally mind blowing depending what you're after. Clearly it depends what games you're playing.
144hz at 1440p would be the perfect balance of visuals and performance some are after.
Do you know model name?
I definitely feel and see the extra smoothness with 120hz over 60, i wouldn't go as far as to say it's a big a leap as seeing from 30fps to 60fps but it's not far off. No doubt 4k is good for certain games that do run well, i see Dirt 3 demoed mainly with 4k and after checking benchmarks i can see why because it runs so well.. but it's not for me at least not for a while.