I had one of these a few months ago but was bitterly disappointed.
It's build quality is poor for a £400 monitor. It wobbles and doesn't feel strong at all. It's riddled with firmware bugs (e.g the blue RGB value not updating when you change it despite it actually making a change, cannot change overdrive settings in Freesync mode, brightness resets when changing certain settings etc). Also had a bright piercing blue light right on the front of the monitor which drove me over the edge. The new revision might fix some of these issues though.
I also doubt it has a good overdrive implementation on this monitor. When I compared it to the Asus MG279Q side by side I noticed the Acer had noticeably more blurring in Testufo and games. Not a great deal more, but it was noticeable and games (mostly fast paced shooters) just didn't feel as pleasant as they did on the Asus.
It's hard to overlook issues like build quality after spending £400 on a monitor. Apart from the Freesync range the Asus MG279Q is the better monitor IMO.