Well the monitor I am looking at is $839 AUD, so that's about $700 U.S. In comparison to what you paid and for what you got at that time this is a much better deal for the upgrade in quality. So why did you pay $1000, what did that screen have that others for $500 didn't?
Top of the line color accurate wide gamut monitor, easy to calibrate, hardware calibration, excellent stability and uniformity, 10 bpc (this one's a nice to have just like 4K). A NEC PA272W is about $1000 without a calibrator where a 27" Eizo Coloredge can set you back $2000 US. The Eizo 23.8" 4K monitor is $2800 US.
IMO these are the highest grade monitors available for photo editing.
You don't have to buy a NEC PA series or Eizo to get a good monitor for editing, just be careful to not select a monitor because it is 4K or 5K as your most important criteria. Maybe this is a bad example, but if a $700 US 4K or 5K monitor has the color accuracy, etc. of a $200 to $300 US 2560 x 1440 monitor (economy IPS) I'd happily give up 4K or 5K and look at a "better" 2560xx1440 monitor that fits the same budget.