I bought one of Overlords Korean 1440p monitors about 2 and a half years ago for $450. It does 120hz with no problems, and the uniformity on it is absolutely perfect. While freesync/gsync and/or backlight strobing and 4K are features id like to have (they dont work together from what i know about them), they are not features that are a big enough jump from this thing to warrant purchasing something newer imo. These new monitors are still 1000:1 contrast IPS panels, just like the one I have, and the picture is not an improvement in any way (especially considering that mine is calibrated with a spectro/colorimeter) save for 4K, but at the cost of refresh rate. On top of that, you read non-stop about uniformity issues and backlight bleeding even on the monitors costing $1000+.
I don't see myself buying another monitor until OLED/QLED or whatever else finally arrives. The contrast of IPS is simply too poor. Having plasma televisions makes it glaringly obvious just how much room there is for improvement when it comes to gaming IQ, even on the very best monitors you can buy. I have 1440p, a high refresh rate, accurate colors, and a panel with uniformity thats extremely uncommon from my experience. I'll be sticking with it for a while.