asus would come out better PC's & Laptops : ASUS K42JA-VX032D Core-i5 ,2gb ATI HD5730 for 43899/- and 3 Assured Gifts
asus laptop screensize is 14 inch, you can check with SMC as well for this model, as ashu already mentioned battery life will be low if not wrong not more than one and half to two hours
also u should have mentioned the different models you looked in
I suggest the asus model + coolermaster laptop cooler + extended warranty for the laptop + addon of RAM, this Asus model is without OS, and gfx card added is much powerful than what is in Dell XPS 15 and yes no need even think about XPS 16.