I thought I read that the 2014 and 2015 MBP 15" units are the same, but I see the Apple store wants $90 more for a refurbed 2015. Can anyone tell me the differences. Also, can anyone comment on my thinking of 13 inch versus 15 inch. I want more memory and disk, and if get a 13 inch with 16 GB and a 512 GB drive the prices really shoots up. Adding the 512 GB to the 15 inch goes up, but not extremely. I prefer the size of the 13 inch, but can "tolerate" with the 15 inch.