Yikes that's a lot of money for a 21:9 UW 1440p monitor that only runs at 60hz.
Regarding screen tearing, yeah VSync/GSync fixes that, but if your PC can't push 60 FPS (on a 60 hz monitor) constantly in a game, you'll notice stuttering with VSync as the GPU tries to maintain the constant. That's why GSync is better, since the monitor itself is re-tuning it self to the videocard's FPS output rather than the other way around, and the GPU can just focus on rendering.
If you realllllly want to game hard, a 4K GSync is probably a better option than a 21:9 UW 1440p (even if it's bigger) like the
Acer XB280HK, but for general use and productivity tasks, it's hard to beat a 21:9.
If you're stuck on a 34" ultra-wide, Acer makes a GSync enabled Predator monitor (the X34) that runs at UW 1440p @ 100hz and it's immaculate, but it's also
$1700.
As a GSync early adopter, I will say, it's a game-changing technology. I'm sure a few of the other GSync owners can chime in about it.
As a side note, UW 21:9 1440p is ~5 million pixels, so a full "4K" monitor (like UHD 3840x2160) would be pushing ~8.3 million, which is like, a pretty huge amount more.