Gsync upgrade worth it?

G-Sync is awesome.

No, I haven't seen it personally. However, I know a lot about computers and have read enough to understand how it works.

Plus, here's a good video (watch the VIDEO) below with Tom Peterson
http://www.geforce.com/hardware/technology/g-sync:

Here's a good review with hands-on experience:
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/64586-week-nvidias-g-sync-monitor.html

Just so it's clear, very few monitors can upgrade, but here's an article discussing how to upgrade the OP's monitor:
http://www.anandtech.com/show/7582/nvidia-gsync-review

The 2nd link in particular should contain all the information you need. Basically, tweak your game to run at around 50 to 60FPS. If the highest settings the game offers run higher that's awesome.

Geforce Experience chooses the game settings to run at 40FPS. With G-Sync that would still be very smooth but I recommend running higher as I said so don't use this feature at all.

I'm not sure why the above guy doesn't care because he "has a 60Hz monitor" but I don't think he quite understands how this works. G-Sync makes the most difference at lower frame rates, but just read the article.
 


Read/watch my links.

It does far more than eliminate screen tearing. VSYNC ON eliminates screen tearing but then you get lag so things feel sluggish. GSYNC eliminates the need for VSYNC so you get minimal lag.

There's also a few other things going on, but basically GSYNC:
1) eliminates screen tearing
2) minimizes the lag of VSYNC
3) reduces STUTTER and JUTTER

Here's a quote from the article:
"Right now, you may think that your current 60Hz or 120Hz panel provides a great experience. I know I did. My tune changed from the moment I started playing Battlefield 4 multiplayer with G-SYNC enabled. "
 


Oh, one thing you didn't mention, when you have 144FPS with V-sync, you get extra latency you don't get at 143 FPS. Due to the polling required with G-sync, it will also increase latency at FPS above ~120-140 FPS. You should set a FPS limiter with G-sync, so it won't get that extra latency in extreme FPS situations. Notice how the FPS limit at 120 performed better than at 143. At 143, it starts behaving like Vsync again. The exact best limit is unclear, but it is somewhere between 120 and 143 FPS.
http://www.blurbusters.com/gsync/preview2/
lag-csgo.png