I am in no way an expert, but I bought the 13in with 8gb 2 days ago and am returning it to get the 16gb. Running Lightroom CC is somewhat sluggish and its the only app open. Activity monitor shows 7gb of memory used consistently all day long with Lightroom using 4gb of that. I figured for an extra $200 it would allow the machine to be a little more future proof for a couple years.