It looks like the T430's best resolution is 1600x900. The ZenBook is 1920x1080, 1.44 times as many pixels. This is the main reason I'm thinking about getting the ZenBook.
I have a Zenbook and love it. Would recommend the UX32VD over the UX31, as you can upgrade the SSD and the RAM. (Jeff Atwood actually uses the UX32VD - he gave the UX31 to his wife.)