The 4k thing brings a problem with tv's.
Manufacturers are now going to consider 1080ptv's as budget tv's so in affect if you buy one I expect you will get a lower quality panel and no HDR, I have not seen any non 4k HDR tv's yet. If you want 10bit console supported HDR but dont care for 4k it seems tough luck, you gotta pay the 4k tv tax to get the HDR.
This hasnt been a problem so much in the PC monitor market, you can buy a high end 1080p monitor today e.g. if wanted. High end is not tied to high resolutions.
Aside from price, a big put off for me with gsync is the restrictions, first gen gsync was one display port only, second gen I believe has added a hdmi but still only one hdmi+DP. I expect any monitor I buy to have at least 3 inputs and to support at least 3 input technologies so I have flexibility. My benq has vga, dvi, hdmi and DP. Ironically out of the 4 its DP I am not using, as DP is an over complicated technology and it seems the DP software is buggy on my screen that DP gets stuck in sleep mode if the monitor is turned off.