Your link says "i5-4210U" --- I point that out because there is a good bit of difference between it and the 5200U.
I think either would be fine for your purposes. I would prefer the AMD but the Intel build has a touchscreen (not a big fan of Dell touchscreens, though). Also -- the last Dell laptop I worked on had an easy access HDD bay on the bottom which made switching to a SSD really simple --- not sure about the Asus but I'm sure you can look it up.
Vegas tends to like AMD GPU Compute, and the Kaveri APU should be good at it in a 'minor league' kind of way. The Turbo on the AMD rig is much higher but it also pulls twice the watts.
The Intel build has 1080p --- the AMD is 720p (not sure that makes a difference to you).
BTW --...