If you arent into fps/multiplayer stuff there is no need for 144hz (my personnel opinion). 4k is something very nice especially in RPG games like Witcher 3. If thats what you play mainly id go for the 4k screen even if youre missing Gsync. Well you get a nice IPS panel instead and the 980ti does totally fine most of the time in 4k. You will run into some issues in some games like Witcher 3 when it comes to maxing out settings @4k with every single GPU available. But a bit lowered settings @4k dont really make a difference.