Most of the people who are buying these Gsync monitors are just being introduced to High Refresh monitors and hyping that aspect in this thread. If you already have a High refresh monitor and upgrading to Gsync, it's not really much of a difference other than judder fix and low response time.
You can disable G-Sync, so you can use the screen as a high refresh rate monitor for comparison.
Having G-Sync enabled makes a big difference in my opinion.
High refresh rate alone isn't worth it. If I'm already paying the premium for a high refresh rate display, I'd pay the extra to get G-Sync. (or FreeSync)
It doesn't make low fps in games to feel 60 fps smooth, it just smooths out the judder. You do still feel the sluggishness of low frame drops.
That's true; any time it drops much below 50-55 FPS or so, things still feel really bad even with G-Sync.
I do think that many people over-hype this aspect of G-Sync - either that or they were already okay with playing games at 30 FPS. (I am not)
But it means that if a game is mostly running at 60+ FPS, you don't notice the small dips below it - which are very noticeable on a 60Hz V-Synced display.
And I can run a game at something like 75-100 FPS and it just feels completely smooth, which is not the case if I use the screen as a fixed refresh rate monitor.
I would have to set it to 75Hz and cap it at that - and even then there will still be times it drops below 75 FPS.
G-Sync is definitely not the end to chasing higher framerates for me.
If anything, the fact that I went from 1080p to 3440x1440 is making me want to upgrade my 1070 to a 1080 Ti, rather than extending its life.
I have been surprised at how well a 1070 is handling that resolution in most games - but I'm still having to tune the settings in some for 60+ FPS, not just setting the game to ultra and playing at whatever it gives me, like some people with G-Sync monitors seem to do.