I have the curved ultrawide G-sync PredatorX34 and it's a great experience. I have a single GTX 980Ti and an i5-4670 (3.4Ghz).
I ran Witcher3 (and both additions) with a minor tweak at 3440x1440 @ 95HZ and it was superb. Doubt I'd notice any difference even if 144HZ were available.
Just finished Rise of the Tomb Raider on similar settings which needed no tweaking although pre-rendered cut scenes remain in 16:9 and it, too was, beautiful.
Depending upon what games you play there may have to be some tweaking if the game is not optimised for 21:9 Ultrawide 3440x1440.
WSGF can help you see what games support that aspect and resolution and guide you on how to tweak the settings - if indeed they can be tweaked.