I am a web developer and I am looking into getting my first mac. Definitely the rMBP 15 is my first choice, but I can save a lot of money if I get the air. Anyone here use the MBA 13 for web development? Do you need 8GB ram or is 4 enough? I'd be doing basic PHP/MySQL and ruby on rails stuff. The laptop would be just for development, no photoshop/video editing/gaming. I prefer the 15" form factor and retina is enticing, but the price different is huge. So I am thinking about getting my feet wet with an MBA, and if I really fall into it I can always sell it and get an rMBP in a year or two. So I am asking if anyone does web dev on their MBA as their primary machine, and what are the pros and cons.