Gotta say I'm pretty disappointed with G-Sync, nearly the point where I'm actually heavily considering reinstalling my old standard board into the monitor.
As someone who's been playing at 144 hz for quite some time, the effects of G-Sync were nearly invisible to me. 144hz on its own eliminated a huge degree of screen tearing for me, and this monitor already has virtually no input lag.
My main purpose of getting G-sync was delay my upgrade by a few years by making sub 60fps gameplay feel much smoother. While G-Sync did make this the case I found that most of the games that slipped below 60 regularly would occasionally hit sub 30 for maybe a second here and there.
And that's when the ceiling comes crashing down.
I had the driver literally crash occasionally when I went sub 30 for a brief second on Skyrim. For the times that it didn't crash, there would be stuttering and lag that simply wasn't a thing on my display pre G-Sync.
I found ULMB to be indistinguishable if not inferior to what was already available for my display using strobelight.
Another issue that I was unaware of: There's no other inputs available for this board. I expected HDMI, VGA, etc inputs to still be available, but simply not work with G-Sync. Instead there's only one input available, which means using this monitor for console use is basically dead.
Admittedly I haven't used G-Sync much for the games that I run at high framerates. I run BF4 on ultra at +80 FPS regularly, never dipping below 60fps, and this is the case for almost any game I play minus Skyrim, which is modded to hell and back and goes sub 30 on occasion due to exceeding my 680 SLI's 2gb VRAM, so there's the possibility that I'll love G-Sync for games that I can run comfortably, but that wasn't the selling point for G-Sync.
Also another point that I don't want to put too much emphasis on because I'm not sure if this is a result of an error during the modding process, but the colors and blacks of the monitor are hugely different from the old board, which looked quite good for a TN panel. I was shocked at seeing how crushed my blacks looked post installation, which was never a thing before. But YMMV on this.
The selling point was a smoother experience for lower frame rates, and I find the technology to be terribly inconsistent/undependable in that area.
Again, this is just an early look, but as of right now it's easily the worse purchase I've made this year.