Either one will be upgraded to 8GB of RAM and an SSD. I plan on using the internet, microsoft word, managing my large iTunes library, and amateur editing in Aperture. I don't plan on doing any gaming or heavy video editing. I feel my uses are pretty basic, aside from Aperture, and I'm hoping I won't notice a difference in performance if I just went with a 13''. So, is a 13'' more than enough to fit my needs for at least the next 3-4 years?