There is a new G-SYNC module in these newer run of monitors, that being said, for every vocal problem with the PG278Q SWIFT there are plenty of *very* happy owners, myself and my roommate included.
It was a first-of-its-kind monitor, there was bound to be bleeding-edge tech issues. Is that "acceptable" for a nearly $800 monitor at launch? That's up for debate, but, every high-end bleeding edge tech product has its issues. Just so happens with a monitor, they're typically immediately obvious since you're staring at it for hours on end.