I think it's the difference between how GSync and FreeSync work. I think the 100/120hz will appear smoother as a result of the technology. Still 144hz is plenty fast where you won't be able to discern the difference, it will come with HDR, and it will cost several hundred less.
WTF cant any of these manufactures make a decent monitor, bought a lg 55" OLED 4k@60hz or 1080p@120hz, HDR, 1ms rs for only $1300 last year. but here, all i see is nothing but compromises no hdr or no gsync, 100hz or 144hz and dont give me that bs of oc to 120hz. but im sure people will bend over for them flashing lights at the back, oh wait even those are a compromise, really cant even put lights on both.
They are both 144Hz native panels, but the G-Sync version cannot run at that due to limitations of the 1.2 G-Sync module it uses, and the fact it only has DP 1.2 connection. The Freesync version does not have this limitation and has a DP 1.4 connection, so can run at the full native speed of the panel. Not that you're getting anywhere near that in games with an AMD card lol!