Currently I have two 27" 1080p monitors but would like to replace them with either two more 27" running at least 1440 or better, or perhaps one single monitor that gives similar total screen area.

Anyone using curved screen i would interested in your experience with them as well as they have possibilities.

See signature below for PC specs the screen(s) are for the primary DAW which is running a ASUS RX560 2GB graphics card.

I just purchased (1 month ago) a Samsung UHD U28E590D 28" monitor. -Native resolution is 3840 X 2160.
It is fabulous. Sorry I waited so long. You didn't mention if you have a separate GPU? I do An MSI GTX1060 6GB and it recommends with this monitor to set screen to 150%. I am assuming it is the card telling me this..........
 
It works out great and I have old eyes also but this is perfect. Got it at Best Buy 

Wook - I have a 43" 4K that is 4 x the screen real estate as a 22" HD.  It is NOT curved.  I do love it.
 
Watch the resolution vs physical size size, AKA pixel density.  I chose the 43" to replace 2 x 22" HD so that the pixel density would be roughly the same.  This means that scaling is NOT necessary to see objects on the screen at the same physical size as I did before.
 
Small, high res displays are where most have trouble because they end up with things too tiny and scale up.  This is problematic because not all applications deal with scaling very well.
 
Just something to watch out for.  If you get it right, you'll wonder why you waited so long to do it
 
 
 

I'm a big Samsung fan. Firstly, due to quality. Secondly, they're the only tech company with service in all 50 states.
 
A few years ago, I bought a Samsung TV. The picture lasted two days at most. Samsung sent a tech to my house to swap out the failed PC board. No charge. No shipping needed. Fixed straightaway.
 
So, here's my next monitor:
 
https://www.samsung.com/us/computing/monitors/curved/34--cf791-wqhd-monitor-lc34f791wqnxza/
 
34" curved Ultra WQHD monitor, $799 list
 

Thanks to you all, I did mention the Graphics card ASUS RX560 2GB Stratman70 but it may well have been easily missed.

Thank you Bob, I will investigate some 43" screens.

Thank you also TheMaartian I will check out your suggestion too.

Well I followed up on all your suggestions had a hunt around and decided to stay using two monitors.  However I did decided that they should be these ones Acer KA270HK 27" 4K UHD Monitor ZeroFrame 5ms  ordered should be here on Wednesday of next week.

Thanks for all the help and advice it is as always greatly appreciated. 

Looks similar to my LG widescreen zero frame. Zero frame is misleading tho as it does appear that way when off, but when on there's a definite 1/2 inch frame at the sides and top so the display doesn't really go edge to edge.