LG's UltraFine 4K display is $524--only $25 extra--until December 31. Afterwards, its price returns to $699.95, which will make it a less attractive option compared to HP's ENVY 27 display, although still worth consideration.
I purchased the LG UltraFine 4K display hoping to use it with my MacBook (native USB-C) and with an older Mac Mini using an adapter that Apple sales person determined would work. The monitor works fine with a native USB-C port (MacBook and new MacBookPro) but I was not able to get it to work on any other Mac even utilizing several different USB-C adapters. Maybe there is a way but I couldn't find it. The HP monitor provides several other connection options (HDMI, etc.) so that would be preferable I believe for anyone wishing to use the monitor on a Mac that does not have USB-C.
I purchased the LG UltraFine 4K display hoping to use it with my MacBook (native USB-C) and with an older Mac Mini using an adapter that Apple sales person determined would work. The monitor works fine with a native USB-C port (MacBook and new MacBookPro) but I was not able to get it to work on any other Mac even utilizing several different USB-C adapters. Maybe there is a way but I couldn't find it. The HP monitor provides several other connection options (HDMI, etc.) so that would be preferable I believe for anyone wishing to use the monitor on a Mac that does not have USB-C.