Im using the UX31A daily since ca. 1 month... ive red the complaints about backlight bleeding and the 1mm higher cassis on the left while opened - laughable in my view. I am absolutely satisfied so far, great Performance, great Keyboard and an amazing high resolution ips screen which is also great for working outside...
http://www.anandtech.com/show/5843/asus-zenbook-prime-ux21a-...