New Asus X556UR owner here. My simple answer, ACER. Now, I may be biased because of the lack of customer service, borderline idiotic CS reps, mis-representation, poor exterior quality, and... should I go on? Needless to say, I will be returning this unit and going with a different brand shortly (within my 30 return policy of course).
If you have the opportunity, def go to a store and do some hands on comparison. See what you are personally comfortable with. Your investment, you should take the extra time to check it out. Don't just go by the specs on various websites, though it's a good place to narrow down the options, when you get to the final 2 or 3, go and see it in person, play with the keyboard, check the layouts, check the quality.