So after a series of faults with my 2012 15" retina 2.6ghz Apple has agreed to replace my laptop with a new 2015 model. The thing is that the '2015' 15" model is only a very small bump from the 2014 model unlike the 13" model that is a proper refresh. My dilemma is that I've already made the decision to switch to a Microsoft surface pro 4 when it's released (I'm a student and that stylus sells it for me) so in terms of raw re-sale value 4 months down the line what do you guys think will fetch more as the 15" is likely to have been refreshed again with skylake/broadwell. In the mean time the laptop will be used lightly, however not much as I own a desktop that serves as my main machine. TLDR; Top of the line 15" vs top of the line 13" MBP Retina resale value in ~4months. n.b This is a very special case where the laptop has been repaired 6 times in 3 years.