MysterD: I have both a 120hz monitor w/ G-Sync on my gaming laptop and also a 240hz G-Synced monitor for my desktop.  
 Yeah, no doubt about - I'll always take 90fps, 120fps, 144fps, 240fps...over 60fps. ANY DAY.  
 And I never thought I needed more than 60fps, when all this rage of G-Sync and higher framerates started going on. And my buddy, he convinced me, when the price was right, to take the pludge.  
 I did. There's no looking back now. 
 StingingVelvet: Yeah. It's kind of a "wish I never experienced it" thing sometimes, because when you have to play a demanding game at 60fps it's a real bummer. Especially first-person games, which is where I notice the drop in framerate the most. I assume I'll be playing Cyberpunk at 60fps and it's a drag. 
 Yep, it's the whole "there's really no looking back type of thing." Once you hit 90fps, 120fps, 144fps, 240fps, etc - yeah, 60fps just....won't do it for you.  
 I get it - at times, I have a game that isn't best put over 60fps b/c of physics going bananas or some other nonsense - i.e. think Fallout 4. And yeah, it's only at 60fps...and it ain't really spectacularly. Isn't as smoother as other games, at better framerates.  
 Throw G-Sync on top...and yeah - again, no looking back; even more. I cringe when a screen tears or I get input lag, if I'm not on my G-Sync monitor.  
 Once you get perfection - or well, close to it, I guess - you can't un-see...what you've already seen.  
 I noticed it for my first time, with GR: Wildlands. It was a game, I had all kinds of issues with. Stutters. Slow downs. Poor framerates (compared to 60fps) on my old rig (i7 950; 16 GB DDR3 RAM; GTX 970; W7 x64). Had to cap it to 40fps, just to keep it stable. Ick.  
 Bought the SC15 laptop b/c I wanted a new laptop and the power/price was good at that time. $1000 on sale (from $2000) - i7 7700 HQ; 16 GB RAM DDR4; 6GB GTX 1060; 15.6'' 120hz G-Sync built-in monitor; TB3; W10 x64. I was in the 90's and took a hit to 60fps. Didn't notice it, except for I saw the framerate dip on the counter in Afterburner. Almost fell out of chair, with it taking such a dip....and didn't notice anything. I realized how right my friend was.  
 Had to test another game. Then tried Prey 2017 - but it was running much better; at 120fps on the SC15. It took a hit to 90fps, when in one of those No-Gravity areas. Again, almost fell out of my damn chair. Didn't notice or feel anything, except saw the framerate take a dive in the counter in Afterburner.  
 First thing I did - began my search for a better monitor w/ G-Sync for my desktop PC. Eventually, I got one.  
 I once thought the jump from 60fps over 30fps was a game-changer. Sure, it was - but high framerates (i.e. 90fps, 120fps, 240fps, etc) with G-Sync is the real game-changer.  
 To me, until I get better equipment and/or prices go down - forget 1440p and 4K at 60fps or lower. Give me 1080p at 90fps or better with G-Sync.