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There were and are still issues with Image retention for a small number of people (all message boards are full of complaints but thats what they are there for and they can scare you if you read too much into them millions of these computers are sold some will have issues).

Many people seem to be very fussy about warmth in their screen but as far as I can tell, apart from a few with genuine concerns, these may well be easy to sort with some screen adjustments or calibration.

I have a late 2013 2.6 512GB 13 inch bought in january and it is just marvelous.
 
The late 2013 and mid 2014 rMBPs seem to be great computers. I wouldn't hesitate to buy a refurbished one.
 
The IR problems were big with the 2012 models; the number of cases severely dropped with the early 2013 models and definitely with the late 2013 one in question. I would say it will likely not be an issue.

And to reassure you, refurbished models actually go through a more in-depth quality check, since there was a problem with the computer in the past. Apple is great with quality products, and I would recommend pulling the trigger and getting the refurb 2013 macbook!

If there are any defects, I do believe the refurbs still have the 1 year warranty that new macbooks have, if that helps to reassure you.
 
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