Definitely wait. GSYNC and ULMB are an enormous upgrade over standard 144hz.
Games that you can't get a steady 144hz still look smooth and without tearing or stuttering which is actually pretty amazing.
The Ultra Low Motion Blur mode is also amazing for games where you can get a steady 120 fps. Motion is soooo much clearer.
I upgraded my VG248QE to GSYNC. It was expensive but definitely worth it. It is one of those upgrades that just make a huge difference. Kind of like going from a standard HDD to an SSD.