Seems like there are serious quality issues with the X34. Have a look at: http://www.overclock.net/t/1537403/tftcentral-acer-predator-xr341ck-34-curved-gaming-screen-with-g-sync/2130#post_24409297 and http://goo.gl/ENrQVu
Reports of color banding, coil whine, backlight bleeding and overclocking issues.
The default panel frequency is even 60hz and not 75hz. For 75hz you need to overclock the X34 and in the manual it is stated that when overclocking it, the risk is at the users end. Ridiculous...
Update:
More reports about a faulty X34 with heavy color banding: http://extreme.pcgameshardware.de/news-kommentare-zu-monitore/395640-acer-predator-x34-gekruemmter-g-sync-monitor-im-juli-fuer-1-400-euro-7.html#post7697276
