Can you help me choose a computer please?

Hi i'm currently looking for a new computer since mine is staring to get very slow (macbook black) i have currently used another computer a friend let me use for the time being me is a macbook pro 15 inch 2011 with AMD Radeon HD 6750M and i've been using steam and done some gaming (portal 2 dota 2 half life 2 tf2 and others) so i'm looking at the asus zenbook ux301 aka infinity and a macbook pro haswell 13 inch which is rumored to have intel 15 4258u and intel iris 5100 and the asus similar specs but i've been practicing c++ to mod games like the ones i mentioned and more and maybe game development so... which one? p.s i know some are going to say build a pc problem i travel a lot like every 1-2 months so i need a laptop.