Is it just a question of weight vs power ? I'm wondering which out the two 13inch 256GB Air vs 13 inch 2.4 GHz MacBook Pro Retina 8GB RAM. Also I'm not sure whether out of the MacBook Pro to go for the 13 inch 8GB memory or 4GB. Any thoughts on this? I do run a fairly large amount of windows open Andy current 2010 white unibody macbook is getting slower.