with the top end ultra wides (z34, z35p, pg348q) you pretty much paying an extra hundred or so for the g sync.
the z35p has shittier viewing angles, higher refresh rate, and is an inch bigger and has VA
x34 has better viewing angles, only 100hz only 34 inch and has ips
I would strongly reccomend the pg348q over the x34 though imo. Dont be worried about light bleed most retailers let you return them now