Dell offers better support (really!) but you'll pay for it.
The two machines are virtually identical in choice of procs, drives etc.. The only real difference is in the available GPU. Asus offers a 2GB nvidia GPU (GT635M) and Dell offers a 1GB AMD (HD7570M) product.
My opinion only: asus use good quality components so life is higher then others.
and also I am used Compaq laptop (c772tu) 6years old but now work without any problems so that's are good in life and low cost but the only problem is not give updated drivers.
Well, my Dell is older (I got it to run OS X). New laptops I've looked at to get seem like ASUS always has better specs, less configurations (great for driver updating), even a better WEI.
I think with Dell there are 2 things- 1. You are paying for the service they provide which I hear is good (but if you have good hardware to begin with, and loads of knowledge, why do you need good service?) 2. They have been branded sooo long, that you are paying for that name and the 'history' or 'longevity' it provides. As an analogy, compare Levi's to an off brand you get at Ross. You wear Levi's, people know it cause of the distinctive tags or looks. Or Carhart or whatever 'well known' brand is. You are then in the current cliche (like when everyone had to have Swatches with Calvin Kleins back in my teenage years!!)