Just picked up a G-Sync monitor for $399 and i feel like i got a free upgrade to a 980ti. I am running a evga gtx 970sc and before gsync i was unable to max out fallout 4 without serious consequences. In most condensed areas i dipped to 30fps. I also returned a 1440p 60hz panel was unable to get past 40 fps on med/high settings. Now if i run dsr at 1440p i get 60-75fps at max settings including maxing auxiliary control panel settings like additional AA SSx8 and texture quality. On the 1080p 144hz panel im getting all the way up to 144fps with super maxed out settings. Prior to my purchase my old 1080p 60hz panel was spiking between 30-60 fps even with v-sync off i could only reach 65fps with horrible stuttering and just plain bad gameplay regardless of vsync enabled or not. I am very happy with my purchase even though others seem to think 1080p gsync is stupid i disagree it is a more noticeable improvement than upgrading to a gtx 970 from a gtx 780. If you can get a sick deal like this on a gsync panel do not hesitate its worth every penny. I would even say for new system builds it may be worth while to downgrade your gpu and fit in g sync into your budget. I am not sure if others experienced this but im shocked at how amazing g sync technology is and its totally underrated. If they can get gsync into the msrp $300-$400 range its going to sell like hot cakes.
If your wondering if its worth it and cant demo it in person I can tell you for a fact its worth it for sure!