I want to change my Macbook Air 13 inch that bought in September 2014 to-date. Air I have a minimum configuration of 128 GB, but I'm with him for 3.5 years, no problems, everything is stored in the cloud and on an external hard drive. I'm starting to do web design, hence is I want a laptop more powerful and with a quality screen (as in the last time more you read from your laptop screen, look at websites, etc.). Some discomfort in working with photoshop on the air is not noticed, only felt 4 GB of RAM not enough, have to close. Now there is money in the minimum configuration MacBook Pro 13 2017 128 GB, tell me, should I buy 256 GB and what is the difference (very much read, but did not understand)? I know that Pro 15 is more powerful, but I want a laptop for the first time with a subsequent update in about 15 if I do all out with the design, now more you want it the retina display. If air was retina display and more RAM, I have hardly changed it.