My first purchase was very disappointing, the screen had an orange "cloud" in the bottom right corner, the menu lever also felt a bit rickety. I sent that screen back and after some further research it turns out that this monitor can be a bit hit or miss in terms of quality. Finally decided to give it another try and ordered a new set. Both screens are excellent this time. Image is great, no weird effects. The menu stick is also a lot stiffer / firmer. Obviously had a Monday morning model the first time.
27” 1440 is a good upgrade over my previous 24” 1080p. The refresh rate is great (especially with GSync). Image is also a bit sharper and the colors are a huge upgrade (first had TN) in short, very satisfied with it!
Another tip for new owners: if you notice that the brightness seems to fluctuate, the monitor has energy saving turned on by default. Turn it off and it won't bother you anymore.