T-Bit

I have the Asus ROG PG348Q, and it totally rocks. Great color right out of the box (remember to reset the blue on X34) and I like the heavier base on the Asus which keeps the feet behind the plane of the screen. The Asus swivels on its base, as does the X34A but not X34. And the user interface is far superior. Other than that consider it a toss up, as technically it is the same panel ;-)

If you can afford G-sync you won't regret it.