Gee. No iris Pro 580 as expected - had decided to go for that... Really makes me wonder which way to go as I'm out on diskspace on my rMBP 2014. My needs are photo editing in Adobe LR and PS. No video editing The 13" has a Iris Pro 550 which is far more powerfull than what i have today. The 15" however "just" has a Iris Pro 530. Assuming that i won't that that much benefit of the Polaris DPGU for my usage? Would the 13" be best choice for my need - any advise? Any advise?